Method for calculating free energy of organic crystal, crystal screening method and related equipment

Abstract

The application discloses a free energy calculation method of an organic crystal. The method comprises the following steps: obtaining a crystal structure of the organic crystal, and initializing a calculation environment according to the crystal structure; performing a calculation operation on the crystal structure according to the initialized calculation environment to obtain a plurality of calculation results, wherein the calculation operation comprises a first calculation operation and a second calculation operation; and performing correction processing on the plurality of calculation results to obtain the vibration free energy of the crystal structure. The application also discloses a screening method of an organic crystal and related equipment. Through the first calculation operation and the second calculation operation on the crystal structure and the correction processing on the plurality of calculation results, the calculation cost of the crystal vibration free energy is reduced while the calculation precision is ensured.

Description

TECHNICAL FIELD

[0001] The disclosed embodiments of the present application relate to the technical field of molecular dynamics, and more particularly, to a free energy calculation method of an organic crystal, a crystal screening method and related equipment. BACKGROUND

[0002] Different crystal packings of a given molecule can exhibit different physical and chemical properties, such as structural stability, solubility, or charge carrier mobility, and so on. Different polymorphs and their relative stabilities are of great value for designing new materials with specific functions. At present, the academic and industrial communities usually predict thermodynamically stable polymorph structures by computational methods. The conventional molecular crystal structure prediction method only considers the stability of the crystal structure at a certain temperature, that is, only considers the contribution of electronic energy to free energy, and ignores other contributions. For example, in actual molecular crystals, the influence of lattice vibration on free energy needs to be considered. That is, accurately handling the crystal vibration free energy for crystal structure prediction of a given molecule is also very important. However, due to the calculation of vibration free energy, it is often necessary to calculate a supercell system of several hundred to thousands of atoms using DFT software, resulting in a particularly high calculation cost. SUMMARY

[0003] According to the embodiments of the present application, a free energy calculation method of an organic crystal, a crystal screening method and related equipment are proposed to solve the problem of high calculation cost when calculating the crystal vibration free energy.

[0004] A first aspect of the present application discloses a free energy calculation method of an organic crystal, comprising: obtaining a crystal structure of the organic crystal, and initializing a calculation environment according to the crystal structure; performing a calculation operation on the crystal structure according to the initialized calculation environment to obtain a plurality of calculation results, wherein the calculation operation includes a first calculation operation and a second calculation operation; and performing correction processing on the plurality of calculation results to obtain the vibration free energy of the crystal structure.

[0005] In some embodiments, before the calculation operation on the crystal structure, the method comprises: calling a preset program to perform structure optimization on the crystal structure to obtain an optimized crystal structure of the crystal structure, wherein the optimized crystal structure satisfies a preset convergence condition.

[0006] In some embodiments, the first computing operation includes a DFT-based operation, and the first computing operation on the crystal structure generates a first computing result, including: based on the optimized crystal structure, generating a plurality of perturbed structures and corresponding configuration files by using a preset software; based on the configuration files, performing batch computing on the plurality of perturbed structures to record data information of the plurality of perturbed structures in the batch computing process; constructing a force constant matrix according to the data information of the plurality of perturbed structures, and then calculating a first phonon frequency of the crystal structure according to the force constant matrix as the first computing result.

[0007] In some embodiments, the plurality of perturbed structures includes a first perturbed structure and a plurality of second perturbed structures, and the first perturbed structure is any one of the plurality of perturbed structures; the batch computing on the plurality of perturbed structures to record the data information of the plurality of perturbed structures in the batch computing process includes: performing static computing on the first perturbed structure, and obtaining wave functions and charge densities of the first perturbed structure after self-consistent convergence; taking the wave functions and charge densities as initial wave functions and initial charge densities of the plurality of second perturbed structures to perform static computing on the plurality of second perturbed structures; and in response to completion of the static computing on the first perturbed structure and the plurality of second perturbed structures, obtaining first force information of the plurality of perturbed structures.

[0008] In some embodiments, the second computing operation includes a DFTB operation, and the second computing operation on the crystal structure generates a second computing result, including: based on the optimized crystal structure, generating a plurality of perturbed structures and corresponding configuration files by using a preset software; based on the configuration files, performing batch computing on the plurality of perturbed structures to record data information of the plurality of perturbed structures in the batch computing process; constructing a force constant matrix according to the data information of the plurality of perturbed structures, and then calculating a second phonon frequency of the crystal structure according to the force constant matrix as the second computing result.

[0009] In some embodiments, before generating the plurality of perturbed structures and the corresponding configuration files by using the preset software, the method further includes: performing structure optimization on the optimized crystal structure by a DFTB method to obtain a DFTB optimized crystal structure, and constructing a supercell structure based on the DFTB optimized crystal structure; and the generating the plurality of perturbed structures and the corresponding configuration files based on the optimized crystal structure by using the preset software includes: generating the plurality of perturbed structures and the corresponding configuration files based on the supercell structure by using the preset software.

[0010] In some embodiments, the batch calculation of the plurality of perturbation structures is performed to record data information of the plurality of perturbation structures in the batch calculation process, including: performing DFTB static calculation on the plurality of perturbation structures; and in response to completion of the static calculation of the plurality of perturbation structures, obtaining second force information of the plurality of perturbation structures.

[0011] In some embodiments, the method further comprises: performing volume changes on the optimized crystal structure according to a preset volume parameter to obtain a plurality of optimized crystal structures with different volumes; and performing structure optimization with limited volume changes on each optimized crystal structure to obtain a plurality of target optimized crystal structures; and performing calculation operations on the crystal structure according to the initial calculation environment to obtain a plurality of calculation results, including: performing calculation operations on each target optimized crystal structure according to the initial calculation environment to obtain a plurality of calculation results corresponding to each target optimized crystal structure.

[0012] In some embodiments, the calculation operation on the crystal structure further comprises: performing stress calculation on the optimized crystal structure satisfying the preset convergence condition in combination with a preset deformation mode to obtain the elastic constant of the crystal structure.

[0013] In some embodiments, the plurality of calculation results include a first calculation result, a second calculation result, and an elastic constant of the crystal structure, wherein the first calculation result is a first phonon frequency of the crystal structure, and the second calculation result is a second phonon frequency of the crystal structure; and the correction processing on the plurality of calculation results to obtain the vibrational free energy of the crystal structure includes: calculating an acoustic branch frequency of the crystal structure according to the elastic constant of the crystal structure; performing matching correction on the first phonon frequency of the crystal structure and the second phonon frequency of the crystal structure by using the acoustic branch frequency and a preset algorithm to obtain a phonon state density of the crystal structure; and determining the vibrational free energy of the crystal structure according to the phonon state density.

[0014] The second aspect of the present application discloses a screening method of organic crystals, comprising: obtaining the vibrational free energy of at least two organic crystals by using the method of the first aspect; and selecting an organic crystal with a vibrational free energy satisfying a preset condition from the at least two organic crystals as a candidate organic crystal.

[0015] The third aspect of the present application discloses a free energy calculation device of an organic crystal, the device comprising: an initialization module configured to obtain a crystal structure of the organic crystal, and initialize a calculation environment according to the crystal structure; a calculation module configured to perform a calculation operation on the crystal structure according to the initialized calculation environment, to obtain a plurality of calculation results, wherein the calculation operation comprises a first calculation operation and a second calculation operation; and a correction processing module configured to perform correction processing on the plurality of calculation results, to obtain a vibrational free energy of the crystal structure.

[0016] The fourth aspect of the present application discloses a screening device of an organic crystal, the device comprising: an obtaining module configured to obtain vibrational free energies of at least two organic crystals by using the method of the first aspect; and a selecting module configured to select an organic crystal whose vibrational free energy satisfies a preset condition from the at least two organic crystals, as a candidate organic crystal.

[0017] The fifth aspect of the present application discloses an electronic device comprising a memory and a processor coupled to each other, wherein the processor is configured to execute program instructions stored in the memory, to implement the free energy calculation method of the organic crystal of the first aspect, or to implement the screening method of the organic crystal of the second aspect.

[0018] The sixth aspect of the present application discloses a non-volatile computer readable storage medium having program instructions stored thereon, wherein the program instructions are executed by a processor to implement the free energy calculation method of the organic crystal of the first aspect, or to implement the screening method of the organic crystal of the second aspect.

[0019] The present application has the following beneficial effects: obtaining a crystal structure, initializing a calculation environment according to the crystal structure, and performing a calculation operation on the crystal structure according to the initialized calculation environment, to obtain a plurality of calculation results, wherein the calculation operation comprises a first calculation operation and a second calculation operation, and further performing correction processing on the plurality of calculation results, to obtain a vibrational free energy of the crystal structure, wherein the first calculation operation and the second calculation operation are performed on the crystal structure, and the correction processing is performed on the plurality of calculation results, to ensure the calculation accuracy and reduce the calculation cost of the crystal vibrational free energy. BRIEF DESCRIPTION OF DRAWINGS

[0020] The present application will be further described below in conjunction with the drawings and embodiments, wherein:

[0021] Figure 1 is a flowchart of the free energy calculation method of the organic crystal of the embodiment of the present application;

[0022] Figure 2 is a flowchart of the screening method of the organic crystal of the embodiment of the present application;

[0023] Figure 3 is a structural schematic diagram of a free energy calculation device of an organic crystal of an embodiment of the present application;

[0024] Figure 4 is a structural schematic diagram of a screening device of an organic crystal of an embodiment of the present application;

[0025] Figure 5 is a phonon density of states diagram of a crystal structure of an embodiment of the present application;

[0026] Figure 6 is a phonon density of states diagram of another crystal structure of an embodiment of the present application;

[0027] Figure 7 is a curve diagram of a vibration free energy of an embodiment of the present application;

[0028] Figure 8 is a structural schematic diagram of an electronic device of an embodiment of the present application;

[0029] Figure 9 is a structural schematic diagram of a non-volatile computer readable storage medium of an embodiment of the present application. DETAILED DESCRIPTION

[0030] Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that any of the embodiments described herein can be combined with any of the other embodiments unless specifically noted otherwise.

[0031] The term "and / or" in the present application is merely used to describe an associated relationship, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally means that the front and rear associated objects are in an "or" relationship. In addition, "multiple" in the present application means two or more than two. In addition, the term "at least one" in the present application means any one of multiple or any combination of at least two of multiple, for example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C. In addition, the terms "first", "second", "third" in the present application are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0032] For the convenience of understanding, the calculation background involved in the present application is explained and described. In a limited temperature, the temperature-dependent part of the Gibbs free energy of the crystal mainly comes from the Helmholtz vibration energy Fvib (Helmholtz vibrationalenergy), which can be obtained by statistical thermodynamics and harmonic approximation:

[0033]

[0034] where F vib is Helmholtz vibrational energy, N A is Avogadro's number, K B is Boltzmann's constant, T is temperature, is reduced Planck's constant, ω is phonon frequency, and g(ω) is phonon state density, that is, the free energy of the crystal can be calculated by the phonon state density of the crystal.

[0035] Calculating the phonon state density requires calculating the phonon dispersion in reciprocal space, that is, constructing a large supercell containing multiple unit cells to describe how the phonon frequency changes with the interaction of its neighboring units. Based on the frozen phonon finite difference displacement method, because the symmetry of the organic molecular crystal is generally low, the number of atoms in the supercell structure is large, and the number of supercell structures is close to thousands, the current consumption of calculating the vibrational free energy in the DFT (Density functional theory) framework is very high. At the same time, it is a particularly time-consuming calculation process to do high-precision DFT structure optimization for a crystal structure with a large number of atoms. Compared with the DFT method, the DFTB (Density Functional based Tight binding method) semi-empirical method is fast and low in calculation cost, but due to the limitation of its principle and method, the free energy calculated by DFTB is less accurate, and cannot meet the free energy accuracy requirement of crystal structure prediction.

[0036] Therefore, the present application provides an organic crystal free energy calculation method, an electronic device and a storage medium.

[0037] In order to enable those skilled in the art to better understand the technical solutions of the present application, the technical solutions of the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0038] Please refer to Figure 1 , Figure 1 is a flowchart of the organic crystal free energy calculation method of the embodiment of the present application. The execution subject of the method can be an electronic device with computing function, for example, microcomputer, server, and mobile device such as notebook computer and tablet computer, etc.

[0039] It should be noted that the method of the present application does not exclude Figure 1The flow sequence shown is limited.

[0040] In some possible implementations, the method can be realized by a processor calling computer-readable instructions stored in a memory, such as Figure 1 As shown, the method can include the following steps:

[0041] S11: Obtain a crystal structure of an organic crystal, and initialize a computing environment according to the crystal structure.

[0042] The crystal structure of the organic crystal is obtained, that is, the number of atoms and the symmetry characteristics of the crystal structure are obtained, and the computing environment is initialized according to the crystal structure. For example, according to the number of atoms and the symmetry characteristics of the crystal structure, the overall computing cost such as core time and memory consumption is predicted by using an empirical estimation script, the empirical estimation script includes calculated structures and accumulated data, and the like, and then the calculation parameter details of the first-principles software such as DFT / DFTB are adjusted to ensure the overall computing efficiency to be optimal, various file configurations required for subsequent calculation are constructed, and the initialization of the computing environment is completed. For example, a vibes program written in a python language is used, a user writes a control input document in a corresponding format, such as a vibes_in.hsd document, for initialization preparation of a free energy computing environment, and the written content can be whether to calculate a quasi-harmonic approximation, whether to use DFTB and DFT, whether to perform structure optimization, whether to use a supercell structure calculation, to use vasp software to calculate elastic constants, to use a stress-strain relationship and maximum strain, and the like.

[0043] S12: According to the initialized computing environment, a computing operation is performed on the crystal structure to obtain a plurality of computing results, wherein the computing operation includes a first computing operation and a second computing operation.

[0044] The computing operation is performed on the crystal structure under the initialized computing environment to obtain a plurality of computing results, that is, data information generated by a plurality of related structures of the crystal in a vibration process, such as atomic force information, dynamic matrix, and frequency information of the crystal obtained by the computing operation, wherein the computing operation includes a first computing operation and a second computing operation. The first computing operation can be a related computing operation based on a density functional theory, and a plurality of first computing results can be obtained, such as computing results obtained under a density functional theory framework; the second computing operation can be a related computing operation based on a density functional tight binding theory, and a plurality of second computing results can be obtained, such as computing results obtained under a density functional tight binding theory framework.

[0045] S13: The plurality of computing results are corrected to obtain a vibration free energy of the crystal structure.

[0046] The plurality of calculation results obtained by the calculation operation on the crystal structure are corrected, that is, the data information of the plurality of calculation results is corrected according to the preset method to obtain higher-precision data. For example, the plurality of frequency data of the crystal are corrected according to the preset method to obtain the frequency of the crystal that meets the condition, and then the vibration free energy of the crystal structure can be obtained through calculation.

[0047] In the embodiment, the calculation environment is initialized according to the obtained crystal structure, and the crystal structure is calculated according to the initialized calculation environment, wherein the calculation operation includes a first calculation operation and a second calculation operation, a plurality of calculation results are obtained, and the plurality of calculation results are corrected to obtain the vibration free energy of the crystal structure. Through the first calculation operation and the second calculation operation on the crystal structure and the correction of the plurality of calculation results, the calculation accuracy is ensured while the calculation cost of the crystal vibration free energy is reduced.

[0048] In some embodiments, before the calculation operation on the crystal structure, the method comprises: calling a preset program to optimize the structure of the crystal structure to obtain an optimized crystal structure of the crystal structure, wherein the optimized crystal structure satisfies a preset convergence condition.

[0049] The preset program is called to optimize the structure of the crystal structure, that is, a DFT program such as VASP, Crystal, FHI-aims, etc. is called. The DFT program includes an internal coordinate structure optimization algorithm. The internal coordinate structure optimization method can be a new coordinate system constructed by bond length, bond angle, and dihedral angle information to represent the positions of atoms in the crystal to optimize the structure and obtain the optimized structure with the lowest energy. The optimization process needs to satisfy a preset convergence condition, for example, the energy difference between this time of crystal structure optimization and the last time of optimization is less than 1e-7eV, and the maximum force on the atom is less than 1e-3eV / A. By using the internal coordinate structure optimization algorithm, the time cost of organic crystal structure optimization can be greatly reduced. Therefore, the subsequent calculation operation on the crystal structure is a calculation operation on the optimized crystal structure.

[0050] In some embodiments, the first calculation operation includes a DFT calculation-based operation. The first calculation operation on the crystal structure is performed to obtain a first calculation result, including: generating a plurality of perturbation structures and corresponding configuration files based on the optimized crystal structure by using a preset software; performing batch calculation on the plurality of perturbation structures based on the configuration files to record data information of the plurality of perturbation structures in the batch calculation process; constructing a force constant matrix according to the data information of the plurality of perturbation structures, and then calculating the first phonon frequency of the crystal structure according to the force constant matrix as the first calculation result.

[0051] The first computing operation includes an operation based on DFT calculation, i.e., calculating the phonon state density by using the DFT method, for example, calculating the supercell structure after completing the DFT optimization. The first computing operation on the crystal structure includes: based on the optimized crystal structure, generating a plurality of perturbation structures and corresponding configuration files by using a preset software, i.e., generating a plurality of perturbation structures and corresponding configuration files by using a preset software on the supercell structure after DFT optimization. For example, a plurality of perturbation structures are generated by using the phonopy software, i.e., a plurality of supercell structures with small "q" displacements in different directions are generated, for example, a structure with 300 atoms may generate 900-2000 perturbation structures, and vasp calculation input files and supercomputing / cloud computing platform configuration files are generated, for example, a script for automatically submitting a platform for calculation, temporary files, calculation result processing scripts, supercell size, and other processing files for which wave functions and charge densities are required to be saved for calculating which crystal structure. Based on the configuration file, a batch calculation is performed on the plurality of perturbation structures to record data information of the plurality of perturbation structures in the batch calculation process, for example, by performing DFT calculation on the plurality of perturbation structures, collecting and recording energy generated in vibration of the plurality of perturbation structures and force data of each atom. The force constant matrix is constructed according to the data information of the plurality of perturbation structures, and then the first phonon frequency of the crystal structure is calculated according to the force constant matrix, for example, the force between atoms in the plurality of perturbation structures is calculated by using the phonopy software to construct the force constant matrix, and then the high-symmetry point (gamma point) frequency is obtained by diagonalizing the force constant matrix, as the first calculation result.

[0052] In some embodiments, the plurality of perturbation structures includes a first perturbation structure and a plurality of second perturbation structures, wherein the first perturbation structure is any one of the plurality of perturbation structures; the batch calculation on the plurality of perturbation structures to record the data information of the plurality of perturbation structures in the batch calculation process includes: performing static calculation on the first perturbation structure, and obtaining the wave function and the charge density of the first perturbation structure after self-consistent convergence; taking the wave function and the charge density as initial wave functions and initial charge densities of the plurality of second perturbation structures to perform static calculation on the plurality of second perturbation structures; and in response to completion of the static calculation of the first perturbation structure and the plurality of second perturbation structures, obtaining the first force information of the plurality of perturbation structures.

[0053] The plurality of perturbation structures includes a first perturbation structure and a plurality of second perturbation structures, wherein the first perturbation structure is any one of the plurality of perturbation structures, for example, can be a first perturbation structure generated based on the DFT-optimized crystal structure by means of the phonopy software, and the first perturbation structure is subjected to static calculation, i.e., self-consistent energy calculation without changing the atomic coordinates, and the wave function 1 and the charge density 1 of the first perturbation structure after self-consistent convergence are output, and the wave function and the charge density of the first perturbation structure after self-consistent convergence are obtained, i.e., the wave function 1 and the charge density 1 of the first perturbation structure after self-consistent convergence are saved. The wave function and the charge density are used as the initial wave function and the initial charge density of the plurality of second perturbation structures to perform static calculation of the plurality of second perturbation structures, i.e., the wave function 1 and the charge density 1 of the first perturbation structure after self-consistent convergence are used as the initial values of the self-consistent calculation of the plurality of second perturbation structures, i.e., the values of the initial wave function and the initial charge density, to accelerate the self-consistent convergence speed of the plurality of second perturbation structures, thereby completing the static calculation of the plurality of perturbation structures. In response to the completion of the static calculation of the first perturbation structure and the plurality of second perturbation structures, i.e., the completion of the static calculation of the plurality of perturbation structures generated by the DFT-optimized unit cell structure by means of the phonopy software, the first force information of the plurality of perturbation structures is obtained, i.e., the atomic force information of each perturbation structure generated by the DFT-optimized unit cell structure is obtained.

[0054] Above, by means of the phonopy+vasp software, a plurality of perturbation structures are generated without cell expansion, and the single-point energy of the first perturbation structure is calculated to obtain the wave function and the charge density; the wave function and the charge density are used as the initial wave function and the initial charge density of other perturbation structures to perform batch single-point energy calculation; atomic force information is collected to construct a dynamic matrix (i.e., a force constant matrix), and the frequency information of the gamma point is calculated.

[0055] In some embodiments, the second calculation operation includes a DFTB calculation operation, and the second calculation operation on the crystal structure to obtain a second calculation result includes: generating a plurality of perturbation structures and corresponding configuration files based on the optimized crystal structure by using a preset software; performing batch calculation on the plurality of perturbation structures based on the configuration file to record data information of the plurality of perturbation structures in the batch calculation process; constructing a force constant matrix according to the data information of the plurality of perturbation structures, and then calculating a second phonon frequency of the crystal structure according to the force constant matrix as the second calculation result.

[0056] The second calculation operation includes an operation based on a DFTB calculation, i.e., calculating a phonon density of states by using a DFTB method, for example, performing a calculation on a crystal cell structure after DFTB optimization, wherein the crystal cell structure after DFTB optimization is based on a crystal cell structure after DFT optimization, and a structure optimization with a constant volume can be performed again by using the DFTB method, for example, the DFTB method can be a DFTB-D3 method, to obtain a steady-state structure of the crystal under the DFTB-D3 standard. The second calculation operation on the crystal structure includes: based on the optimized crystal structure, generating a plurality of perturbation structures and corresponding configuration files by using a preset software, i.e., generating a plurality of perturbation structures and corresponding configuration files by using a preset software based on the crystal cell structure after DFTB optimization, for example, generating a plurality of perturbation structures by using the phonopy software, i.e., generating supercell structures with small "q" displacements in different directions, for example, a structure with 300 atoms can generate 900-2000 perturbation structures, and generating DFTB calculation input files and configuration files of a supercomputer / cloud computing platform, for example, a script for automatically submitting a calculation to the platform, temporary files, a script for processing calculation results, the size of the supercell, and other processing files such as wave functions and charge densities required for crystal structure calculation. Based on the configuration files, a batch calculation is performed on the plurality of perturbation structures to record data information of the plurality of perturbation structures in the batch calculation process, for example, by performing DFTB calculations on the plurality of perturbation structures, collecting and recording energy generated in the vibration of the plurality of perturbation structures and force data of each atom. A force constant matrix is constructed based on the data information of the plurality of perturbation structures, and then a first phonon frequency of the crystal structure is calculated based on the force constant matrix, for example, the force between atoms in the plurality of perturbation structures is calculated by using the phonopy software to construct the force constant matrix, and the high-symmetry point (gamma point) frequency and the displacement point (q point) frequency are obtained by diagonalizing the force constant matrix, as the second calculation result.

[0057] In some embodiments, before generating a plurality of perturbation structures and corresponding configuration files by using a preset software, the method further includes: performing a structure optimization on the optimized crystal structure by using a DFTB method to obtain a DFTB-optimized crystal structure, and constructing a supercell structure based on the DFTB-optimized crystal structure; and based on the optimized crystal structure, generating a plurality of perturbation structures and corresponding configuration files by using a preset software, including: based on the supercell structure, generating a plurality of perturbation structures and corresponding configuration files by using a preset software.

[0058] The optimized crystal structure is subjected to structure optimization in a DFTB mode, wherein the optimized crystal structure is a crystal structure that has completed structure optimization by calling a preset program, such as a DFT cell structure obtained by calling a DFT program. The optimized crystal structure is subjected to structure optimization in a DFTB mode to obtain a DFTB-optimized crystal structure, such as a DFTB-D3 method for re-optimizing the structure without changing the volume to obtain a steady-state structure under the DFTB-D3 standard. Based on the DFTB-optimized crystal structure, a supercell structure is constructed, that is, the steady-state structure under the DFTB-D3 standard is used to construct a supercell structure by means of phonopy software. Further, based on the supercell structure, a plurality of perturbation structures and corresponding configuration files are generated by using a preset software, such as constructing a supercell structure based on the DFTB-optimized crystal structure, generating a plurality of supercell perturbation structures by using phonopy software, and generating DFTB calculation input files and configuration files of a supercomputer / cloud computing platform for calculation to obtain atomic force information of the crystal.

[0059] In some embodiments, batch calculation is performed on the plurality of perturbation structures to record data information of the plurality of perturbation structures in the batch calculation process, including: performing DFTB static calculation on the plurality of perturbation structures; and obtaining second force information of the plurality of perturbation structures in response to completion of the static calculation of the plurality of perturbation structures.

[0060] The plurality of perturbation structures are subjected to DFTB static calculation, such as DFTB-D3 static calculation, wherein the perturbation structures are a plurality of supercell perturbation structures generated by constructing a supercell structure by using the steady-state structure under the DFTB-D3 standard by means of phonopy software, such as the steady-state structure under the DFTB-D3 standard being obtained by optimizing the DFT-optimized cell structure by using the DFTB-D3 method. In response to completion of the static calculation of the plurality of perturbation structures, the second force information of the plurality of perturbation structures is obtained, that is, in response to completion of the static calculation of the plurality of perturbation structures, the atomic force information of each perturbation structure generated by the DFTB-optimized cell structure is obtained, such as the direction, size, etc. of the atomic force in the organic crystal.

[0061] Again, the phonopy software can be used to construct a supercell with a proper size (for example, the lattice in each direction is kept ), generate a plurality of supercell perturbation structures, and calculate the single-point energy of the first supercell perturbation structure to obtain the charge density; the charge density is used as the initial charge density of other supercell perturbation structures for batch single-point energy calculation; atomic force information is collected to construct a dynamic matrix (i.e. a force constant matrix), and the frequency information of the gamma point and the frequency information of the q point are calculated.

[0062] In some embodiments, before the computing operation on the crystal structure, further comprising: performing multiple volume changes on the optimized crystal structure according to preset volume parameters to obtain multiple optimized crystal structures at different volumes; and performing volume-constrained structure optimization on the optimized crystal structure at each volume to obtain multiple target optimized crystal structures.

[0063] The optimized crystal structure of the crystal structure is subjected to multiple volume changes, wherein the optimized crystal structure of the crystal structure can be a DFT-optimized unit cell structure, for example, a series of volume changes are applied to the DFT-optimized unit cell structure to obtain a series of new unit cell structures. The optimized crystal structure at each volume is subjected to volume-constrained structure optimization to obtain multiple target optimized crystal structures, for example, a series of new unit cell structures are obtained by performing multiple volume changes on the optimized crystal structure, and structure optimization is performed by maintaining the corresponding volume, for example, DFT is used for structure optimization, to obtain multiple target optimized crystal structures.

[0064] The preset volume parameters can be different volume sizes set in advance, that is, the optimized crystal structure is subjected to volume changes according to the set different volume parameters, instead of blindly changing the volume.

[0065] Further, each target optimized crystal structure obtained can be subjected to the computing operation according to the method described in the above embodiments to obtain multiple calculation results corresponding to each target optimized crystal structure, and the vibration free energy corresponding to each target optimized crystal structure is obtained according to the calculation results. The above process considers the quasi-harmonic calculation process and can obtain thermodynamic data under a certain pressure, thereby meeting more extensive business requirements.

[0066] In some embodiments, the computing operation on the crystal structure further comprises: performing stress calculation on the optimized crystal structure satisfying the preset convergence condition in combination with a preset deformation mode to obtain the elastic constant of the crystal structure.

[0067] The computing operation on the crystal structure further includes stress calculation on the optimized crystal structure satisfying the preset convergence condition in combination with a preset deformation mode, for example, the DFTB / DFT method or the force field method can be used for calculation, wherein the optimized crystal structure satisfying the preset convergence condition, for example, the energy difference between this time of crystal structure optimization and the last time of optimization is less than a preset difference value (such as 1e-7 eV), and / or the maximum stress of the atom is less than a preset stress (such as 1e-3 eV / A). The elastic constant is calculated by using the DFTB / DFT method, that is, the crystal cell structure after DFT optimization is used, different deformation modes are applied according to the crystal symmetry, the stress is calculated by using the DFT method, and the elastic constant of the corresponding crystal is obtained according to the stress-strain relationship, wherein the deformation mode can be selected according to different crystal structures; or the crystal cell structure after DFTB optimization is used, different deformation modes are applied according to the crystal symmetry, wherein the crystal cell structure after DFTB optimization is based on the crystal cell structure after DFT optimization, the stress is calculated by using the DFTB method, and the elastic constant of the corresponding crystal is obtained according to the stress-strain relationship, wherein the deformation mode can be selected according to different crystal structures.

[0068] In some embodiments, the plurality of calculation results include a first calculation result, a second calculation result, and an elastic constant of the crystal structure, wherein the first calculation result is a first phonon frequency of the crystal structure, and the second calculation result is a second phonon frequency of the crystal structure; and the correction processing on the plurality of calculation results to obtain the vibrational free energy of the crystal structure includes: calculating an acoustic branch frequency of the crystal structure according to the elastic constant of the crystal structure; performing matching correction on the first phonon frequency of the crystal structure and the second phonon frequency of the crystal structure by using the acoustic branch frequency and a preset algorithm to obtain a phonon density of states of the crystal structure; and determining the vibrational free energy of the crystal structure according to the phonon density of states.

[0069] The computing operation on the crystal structure obtains a plurality of calculation results, wherein the plurality of calculation results include a first calculation result, a second calculation result, and an elastic constant of the crystal structure, wherein the first calculation result is a first phonon frequency of the crystal structure, that is, a high-symmetry point (gamma point) frequency of the crystal calculated based on the DFT method; the second calculation result is a second phonon frequency of the crystal structure, that is, a high-symmetry point (gamma point) frequency and a displacement point (q point) frequency of the crystal calculated based on the DFTB method; and the elastic constant of the crystal structure, wherein the elastic constant describes the stiffness of the response of the crystal to an external strain.

[0070] Further, the plurality of calculation results are corrected, for example, the plurality of calculation results include the first phonon frequency of the crystal structure, the second phonon frequency of the crystal structure, and the elastic constant of the crystal structure. The acoustic branch frequency of the crystal structure is calculated according to the elastic constant of the crystal structure, for example, the acoustic branch frequency can be calculated by the Deby-like model, so as to calculate the acoustic branch frequency of the crystal structure by the elastic constant of the crystal structure. Then, the first phonon frequency of the crystal structure and the second phonon frequency of the crystal structure are matched and corrected by using the acoustic branch frequency and a preset algorithm, wherein the preset algorithm can be obtained by combining the Mode Matching method with an empirical correction equation, for example, can be combined with the Deby-like model acoustic branch frequency and the stable-marriage matching algorithm.

[0071] The main formula in the Mode Matching method is as follows:

[0072]

[0073] ω q (q) is the frequency of the crystal, i (q) is the frequency of the crystal, is the q-point frequency of the crystal structure calculated by the DFTB method, is the gamma-point frequency of the crystal structure calculated by the DFT method, is the gamma-point frequency of the crystal structure calculated by the DFTB method.

[0074] That is, the gamma-point phonon frequency and other q-point frequencies calculated by the DFTB method are respectively subtracted from the gamma-point frequency calculated by the DFT method, so as to correct the arbitrary q-point frequencies obtained by the DFTB method and the DFT, and then the phonon density of states of the crystal structure is obtained by calculation, so as to determine the free energy of the crystal structure according to the phonon density of states.

[0075] Please refer to Figure 2 , Figure 2 is a flowchart of the screening method of the organic crystal according to the embodiments of the present application. The execution subject of the method can be an electronic device with computing function, for example, a microcomputer, a server, and a mobile device such as a notebook computer and a tablet computer.

[0076] It should be noted that, if there are substantially the same results, the method of the present application is not limited to the order of the flowchart shown in Figure 2 .

[0077] In some possible implementation manners, the method can be realized by a processor calling computer readable instructions stored in a memory, as shown in Figure 2 , the method can include the following steps:

[0078] S21: Obtain the vibrational free energy of at least two organic crystals by using the above-mentioned free energy calculation method of organic crystals.

[0079] The at least two organic crystals can be a set of different crystal packings of a given molecule. The vibrational free energy of the at least two organic crystals is obtained by using the above-mentioned free energy calculation method of organic crystals, i.e., obtaining the crystal structure, and initializing the calculation environment according to the crystal structure, and performing calculation operations on the crystal structure according to the initialized calculation environment, wherein the calculation operations include first calculation operations and second calculation operations, for example, the first calculation operations can be DFT-based calculation operations, and the second calculation operations can be DFTB-based calculation operations, and then a plurality of calculation results can be obtained.

[0080] Further, the plurality of calculation results are corrected to obtain the vibrational free energy of the crystal structure, wherein the calculation results include first calculation results, second calculation results, and elastic constants of the crystal structure, for example, the acoustic branch frequency of the crystal structure can be calculated according to the elastic constants of the crystal structure, and the first phonon frequency of the crystal structure and the second phonon frequency of the crystal structure are matched and corrected by using the acoustic branch frequency and a preset algorithm to obtain the phonon density of states of the crystal structure, and the vibrational free energy of the crystal structure is determined according to the phonon density of states.

[0081] S22: Select an organic crystal whose vibrational free energy meets a preset condition from the at least two organic crystals as a candidate organic crystal.

[0082] The vibrational free energy of at least two organic crystals is obtained by using the above-mentioned free energy calculation method of organic crystals, for example, the vibrational free energy a of the organic crystal A1 and the vibrational free energy b of the organic crystal A2 are obtained, wherein a < b. An organic crystal whose vibrational free energy meets a preset condition is selected from the at least two organic crystals as a candidate organic crystal, for example, an organic crystal whose vibrational free energy meets a preset condition is selected from the organic crystal A1 and the organic crystal A2, wherein the preset condition can be to select the organic crystal with the lowest energy as the candidate organic crystal, i.e., to select the organic crystal A1 as the candidate organic crystal.

[0083] In addition, the vibrational free energy of any two organic crystals can also be calculated based on the above-mentioned free energy calculation method of organic crystals, and the relative vibrational free energy difference of different configuration crystals can be obtained by calculating the difference between the two.

[0084] Please refer to Figure 3 , Figure 3 is a structural schematic diagram of the free energy calculation device of the organic crystal of the embodiment of the present application. The free energy calculation device 300 of the organic crystal includes an initialization module 310, a calculation module 320, and a correction processing module 330.

[0085] The initialization module 310 is configured to obtain a crystal structure of an organic crystal, and initialize a calculation environment according to the crystal structure.

[0086] The calculation module 320 is configured to perform a calculation operation on the crystal structure according to the initialized calculation environment, to obtain a plurality of calculation results, wherein the calculation operation includes a first calculation operation and a second calculation operation.

[0087] The correction processing module 330 is configured to perform correction processing on the plurality of calculation results, to obtain a vibrational free energy of the crystal structure.

[0088] The free energy calculation device 300 for the organic crystal is configured to initialize a calculation environment for the obtained crystal structure, and perform a calculation operation on the crystal structure according to the initialized calculation environment, to obtain a plurality of calculation results, and perform correction processing on the plurality of calculation results, to obtain a free energy of the crystal structure, thereby ensuring calculation accuracy and reducing the calculation cost of the crystal vibrational free energy.

[0089] In some embodiments, the initialization module 310 calls a preset program to perform structure optimization on the crystal structure, to obtain an optimized crystal structure of the crystal structure, wherein the optimized crystal structure satisfies a preset convergence condition.

[0090] In some embodiments, the first calculation operation includes a DFT calculation-based operation, and the calculation module 320 performs the first calculation operation on the crystal structure to obtain a first calculation result, including: based on the optimized crystal structure, generating a plurality of perturbation structures and corresponding configuration files by using a preset software, performing batch calculation on the plurality of perturbation structures based on the configuration files, recording data information of the plurality of perturbation structures in the batch calculation process, and constructing a force constant matrix according to the data information of the plurality of perturbation structures, and then calculating a first phonon frequency of the crystal structure according to the force constant matrix as the first calculation result.

[0091] In some embodiments, the plurality of perturbation structures includes a first perturbation structure and a plurality of second perturbation structures, wherein the first perturbation structure is any one of the plurality of perturbation structures, the calculation module 320 is configured to perform static calculation on the first perturbation structure, and obtain a wave function and a charge density of the first perturbation structure after self-consistent convergence, and take the wave function and the charge density as initial wave functions and initial charge densities of the plurality of second perturbation structures, to perform static calculation on the plurality of second perturbation structures, and obtain first force information of the plurality of perturbation structures in response to completion of the static calculation of the first perturbation structure and the plurality of second perturbation structures.

[0092] In some embodiments, the second computing operation comprises an operation of a DFTB calculation, and the computing module 320 performs the second computing operation on the crystal structure to obtain a second computing result, including: based on the optimized crystal structure, generating a plurality of perturbation structures and corresponding configuration files by using a preset software, performing batch computing on the plurality of perturbation structures based on the configuration files, recording data information of the plurality of perturbation structures in the batch computing process, and constructing a force constant matrix according to the data information of the plurality of perturbation structures, and then calculating a second phonon frequency of the crystal structure according to the force constant matrix as the second computing result.

[0093] In some embodiments, the initialization module 310 is further configured to perform structure optimization on the optimized crystal structure by a DFTB method before generating the plurality of perturbation structures and the corresponding configuration files by using the preset software, to obtain a DFTB optimized crystal structure, and construct a supercell structure based on the DFTB optimized crystal structure.

[0094] Correspondingly, the computing module 320 generates the plurality of perturbation structures and the corresponding configuration files by using the preset software based on the optimized crystal structure, including: generating the plurality of perturbation structures and the corresponding configuration files by using the preset software based on the supercell structure.

[0095] In some embodiments, the computing module 320 is configured to perform DFTB static computing on the plurality of perturbation structures, and in response to completion of the static computing on the plurality of perturbation structures, obtain second stress information of the plurality of perturbation structures.

[0096] In some embodiments, the computing module 320 performs volume change on the optimized crystal structure according to a preset volume parameter for a plurality of times to obtain a plurality of optimized crystal structures with different volumes, and performs structure optimization with volume limitation on each optimized crystal structure with a volume to obtain a plurality of target optimized crystal structures after optimization.

[0097] Correspondingly, the computing module 320 performs computing operation on each target optimized crystal structure according to the initialized computing environment to obtain a plurality of computing results corresponding to each target optimized crystal structure.

[0098] In some embodiments, the computing module 320 is configured to perform stress calculation on the optimized crystal structure satisfying the preset convergence condition in combination with a preset deformation mode to obtain the elastic constant of the crystal structure.

[0099] In some embodiments, the multiple calculation results include a first calculation result, a second calculation result, and the elastic constants of the crystal structure, wherein the first calculation result is the first phonon frequency of the crystal structure, and the second calculation result is the second phonon frequency of the crystal structure. The correction processing module 330 is used to calculate the acoustic branch frequencies of the crystal structure based on the elastic constants of the crystal structure, and to perform matching correction on the first phonon frequency and the second phonon frequency of the crystal structure using the acoustic branch frequencies and a preset algorithm to obtain the phonon density of states of the crystal structure, and to determine the vibrational free energy of the crystal structure based on the phonon density of states.

[0100] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of an organic crystal screening device according to an embodiment of this application. The organic crystal screening device 400 includes an acquisition module 410 and a selection module 420.

[0101] The acquisition module 410 is used to acquire the vibrational free energy of at least two organic crystals using the above-mentioned free energy calculation method for organic crystals.

[0102] At least two organic crystals can be a collection of organic crystals with different crystal stacks of a given molecule. The acquisition module 410 is used to acquire the vibrational free energy of at least two organic crystals, i.e., the acquired crystal structure, using the free energy calculation method of organic crystals described above, and initialize the calculation environment according to the crystal structure. The calculation operation is performed on the crystal structure according to the initialized calculation environment. The calculation operation includes a first calculation operation and a second calculation operation. For example, the first calculation operation can be a DFT-based operation and the second calculation operation can be a DFTB-based operation, thereby obtaining multiple calculation results.

[0103] Furthermore, the acquisition module 410 is used to correct multiple calculation results to obtain the vibrational free energy of the crystal structure. The calculation results include a first calculation result, a second calculation result, and the elastic constants of the crystal structure. For example, the acoustic branch frequency of the crystal structure can be calculated based on the elastic constants of the crystal structure, and the first phonon frequency and the second phonon frequency of the crystal structure can be matched and corrected using the acoustic branch frequency and a preset algorithm to obtain the phonon density of states of the crystal structure, and the vibrational free energy of the crystal structure can be determined based on the phonon density of states.

[0104] The selection module 420 is used to select an organic crystal whose vibrational free energy satisfies a preset condition from at least two organic crystals as a candidate organic crystal.

[0105] As described above, the vibration free energy of at least two organic crystals is obtained by using the free energy calculation method of the organic crystal, for example, the vibration free energy a of the organic crystal A1 and the vibration free energy b of the organic crystal A2 are obtained, wherein a < b. The selection module 420 is used to select the organic crystal with vibration free energy meeting the preset condition from the at least two organic crystals as the candidate organic crystal, for example, the vibration free energy of the organic crystal A1 and the organic crystal A2 is selected, wherein the preset condition can be to select the organic crystal with the lowest energy as the candidate organic crystal, that is, the organic crystal A1 is selected as the candidate organic crystal.

[0106] In order to more clearly understand the present application, the actual use examples of the technical solutions of the present application are described below, for example, the structures A and B of 2 CHNO systems are calculated, the space group number is 4, the number of atoms is 98, and the supercell size is 2x1x1.

[0107] In the calculation process, the DFT part adopts the VASP software, the cutoff energy is 600eV, the accuracy is high, the energy convergence accuracy is 1e-7eV, the force convergence is 1e-3eV / A, and the DFTB uses the latest 2022 version of dftbplus. After completing the calculation processing, the corrected phonon density diagram is obtained, as shown in Figures 5-6 Figure 5 is the phonon density diagram of a crystal structure of an embodiment of the present application, that is, the phonon density of structure A, Figure 6 is the phonon density diagram of another crystal structure of an embodiment of the present application, that is, the phonon density of structure B.

[0108] As shown in Figure 7 Figure 7 is a curve diagram of the vibration free energy of an embodiment of the present application, the vibration free energy between structure A and structure B is calculated by different methods, for example, the relative free energy calculated by using the supercell method with pure DFT as the reference, the DFT-SuperCell curve in Figure 7 can be obtained. The technical solution in the present application adopts DFT to calculate the unit cell and the acoustic branch frequency after correction, corresponding to the DFT-Unit-ECS curve in Figure 7 It can be seen that the relative free energy calculated by the technical solution of the present application is very small, about 1.3kj / mol, compared with the DFT method with the longest time, and the calculation cost is about 1 / 10 of the pure DFT supercell calculation, that is, the calculation cost of the crystal vibration free energy is reduced while the calculation accuracy is guaranteed.

[0109] Those skilled in the art can understand that in the above method of the specific implementation manner, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process, and the specific execution order of each step should be determined by its function and possible internal logic. ​​

[0110] Please refer to Figure 8 , Figure 8 is a structural schematic diagram of an electronic device of an embodiment of the present application. The electronic device 80 comprises a memory 81 and a processor 82 coupled with each other. The processor 82 is configured to execute program instructions stored in the memory 81 to implement the steps of the above-mentioned embodiments of the free energy calculation method of organic crystal. In a specific implementation scenario, the electronic device 80 can include but is not limited to a microcomputer, a server, without limitation.

[0111] Specifically, the processor 82 is configured to control itself and the memory 81 to implement the steps of the above-mentioned embodiments of the free energy calculation method of organic crystal. The processor 82 can also be referred to as a CPU (Central Processing Unit). The processor 82 can be an integrated circuit chip with processing capability. The processor 82 can also be a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. In addition, the processor 82 can be implemented by an integrated circuit chip.

[0112] Please refer to Figure 9 , Figure 9 is a structural schematic diagram of a non-volatile computer readable storage medium of an embodiment of the present application. The non-volatile computer readable storage medium 90 is configured to store a computer program 901. When the computer program 901 is executed by a processor, for example, the processor 82 in the above-mentioned embodiments of the free energy calculation method of organic crystal, the computer program 901 is configured to implement the steps of the above-mentioned embodiments of the free energy calculation method of organic crystal. Figure 8

[0113] The above description of various embodiments tends to emphasize the differences between various embodiments, and the same or similar parts can be mutually referred to, and for the sake of brevity, will not be repeated here.

[0114] ​In several embodiments provided in the present application, it should be understood that the disclosed methods and related devices can be implemented in other manners. For example, the described embodiments of the related devices are merely schematic. For example, the division of the modules or units is merely logical function division. There can be another division manner for the actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0115] In addition, each function unit in the embodiments of the present application can be integrated into a processing unit, or each unit can exist alone physically, or two or more units can be integrated into one unit. The integrated unit can be implemented in the form of hardware, or in the form of a software function unit.

[0116] If the integrated unit is implemented in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on such an understanding, the technical solutions of the present application essentially, or the part that contributes to the prior art, or all or a part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the methods in the embodiments of the present application. The foregoing storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk, and various other media that can store program codes.

[0117] It is easy for those skilled in the art to make modifications and variations to the device and method while keeping the teachings of the present application. Therefore, the above disclosure should be regarded as limited only by the scope of the appended claims.

Claims

1. A method for calculating the free energy of an organic crystal, characterized in that, include: Obtain the crystal structure of the organic crystal, and initialize the computing environment based on the crystal structure; Based on the initialization computing environment, calculation operations are performed on the crystal structure to obtain multiple calculation results, wherein the calculation operations include a first calculation operation and a second calculation operation; The multiple calculation results are corrected to obtain the vibrational free energy of the crystal structure; The plurality of calculation results include a first calculation result, a second calculation result, and the elastic constant of the crystal structure, wherein the first calculation result is the first phonon frequency of the crystal structure, and the second calculation result is the second phonon frequency of the crystal structure; The step of correcting the multiple calculation results to obtain the vibrational free energy of the crystal structure includes: Calculate the acoustic branch frequencies of the crystal structure based on the elastic constants of the crystal structure; The first phonon frequency and the second phonon frequency of the crystal structure are matched and corrected using the acoustic branch frequency and a preset algorithm to obtain the phonon state density of the crystal structure. The vibrational free energy of the crystal structure is determined based on the phonon state density.

2. The method according to claim 1, characterized in that, Before performing calculations on the crystal structure, the following steps are included: A preset program is invoked to optimize the crystal structure to obtain an optimized crystal structure, wherein the optimized crystal structure satisfies a preset convergence condition.

3. The method according to claim 2, characterized in that, The first calculation operation includes a DFT-based calculation operation, which is performed on the crystal structure to obtain a first calculation result, including: Based on the optimized crystal structure, multiple perturbation structures and corresponding configuration files are generated using preset software. Based on the configuration file, batch calculations are performed on the multiple perturbation structures to record the data information of the multiple perturbation structures during the batch calculation process; A force constant matrix is ​​constructed based on the data information of the multiple perturbation structures, and then the first phonon frequency of the crystal structure is calculated based on the force constant matrix, which is used as the first calculation result.

4. The method according to claim 3, characterized in that, The plurality of perturbation structures include a first perturbation structure and a plurality of second perturbation structures, wherein the first perturbation structure is any one of the plurality of perturbation structures. Batch calculations are performed on the multiple perturbation structures to record data information of the multiple perturbation structures during the batch calculation process, including: Static calculations are performed on the first perturbation structure to obtain the wave function and charge density of the first perturbation structure after self-consistent convergence. The wave function and charge density are used as the initial wave function and initial charge density of the plurality of second perturbation structures to perform static calculations of the plurality of second perturbation structures; In response to the completion of static calculations of the first perturbation structure and the plurality of second perturbation structures, the first force information of the plurality of perturbation structures is obtained.

5. The method according to claim 2, characterized in that, The second calculation operation includes a DFTB calculation operation. The second calculation operation is performed on the crystal structure to obtain a second calculation result, including: Based on the optimized crystal structure, multiple perturbation structures and corresponding configuration files are generated using preset software. Based on the configuration file, batch calculations are performed on the multiple perturbation structures to record the data information of the multiple perturbation structures during the batch calculation process; A force constant matrix is ​​constructed based on the data information of the multiple perturbation structures, and then the second phonon frequency of the crystal structure is calculated based on the force constant matrix, which is used as the second calculation result.

6. The method according to claim 5, characterized in that, Before generating multiple perturbation structures and corresponding configuration files using preset software, the process also includes: The optimized crystal structure is structurally optimized using the DFTB method to obtain a DFTB-optimized crystal structure, and a supercell structure is constructed based on the DFTB-optimized crystal structure. Based on the optimized crystal structure, multiple perturbation structures and corresponding configuration files are generated using preset software, including: Based on the supercell structure, multiple perturbation structures and corresponding configuration files are generated using preset software.

7. The method according to claim 6, characterized in that, Batch calculations are performed on the multiple perturbation structures to record data information of the multiple perturbation structures during the batch calculation process, including: DFTB static calculations were performed on the multiple perturbation structures; In response to the completion of static calculations of the plurality of perturbation structures, the second force information of the plurality of perturbation structures is obtained.

8. The method according to claim 2, characterized in that, The method further includes: The optimized crystal structure is subjected to multiple volume changes according to preset volume parameters to obtain multiple optimized crystal structures with different volumes; For each volume, the optimized crystal structure is subjected to structural optimization with restricted volume changes, resulting in multiple optimized target crystal structures. The calculation operation is performed on the crystal structure according to the initialization calculation environment to obtain multiple calculation results, including: Based on the initialization computing environment, calculation operations are performed on each of the target optimized crystal structures to obtain multiple calculation results corresponding to each target optimized crystal structure.

9. The method according to claim 2, characterized in that, The calculation operation on the crystal structure further includes: By combining the preset deformation method, stress calculation is performed on the optimized crystal structure that meets the preset convergence condition to obtain the elastic constant of the crystal structure.

10. A method for screening organic crystals, characterized in that, include: The vibrational free energies of at least two organic crystals are obtained using the method described in any one of claims 1-9; From the at least two organic crystals, select an organic crystal whose vibrational free energy satisfies a preset condition as a candidate organic crystal.

11. A device for calculating the free energy of an organic crystal, characterized in that, The device includes: An initialization module is used to obtain the crystal structure of the organic crystal and initialize the computing environment based on the crystal structure. The calculation module is used to perform calculation operations on the crystal structure according to the initialization calculation environment to obtain multiple calculation results, wherein the calculation operations include a first calculation operation and a second calculation operation. A correction processing module is used to correct the multiple calculation results in order to obtain the vibrational free energy of the crystal structure. The plurality of calculation results include a first calculation result, a second calculation result, and the elastic constant of the crystal structure, wherein the first calculation result is the first phonon frequency of the crystal structure, and the second calculation result is the second phonon frequency of the crystal structure; The correction processing module corrects the multiple calculation results to obtain the vibrational free energy of the crystal structure, including: Calculate the acoustic branch frequencies of the crystal structure based on the elastic constants of the crystal structure; The first phonon frequency and the second phonon frequency of the crystal structure are matched and corrected using the acoustic branch frequency and a preset algorithm to obtain the phonon state density of the crystal structure. The vibrational free energy of the crystal structure is determined based on the phonon state density.

12. A screening device for organic crystals, characterized in that, The device includes: An acquisition module is used to acquire the vibrational free energy of at least two organic crystals using the method described in any one of claims 1-9; The selection module selects an organic crystal whose vibrational free energy satisfies a preset condition from the at least two organic crystals as a candidate organic crystal.

13. An electronic device, characterized in that, It includes a memory and a processor coupled to each other, the processor being configured to execute program instructions stored in the memory to implement the free energy calculation method for organic crystals according to any one of claims 1 to 9, or to implement the screening method for organic crystals according to claim 10.

14. A non-volatile computer-readable storage medium storing program instructions thereon, characterized in that, When the program instructions are executed by the processor, they implement the free energy calculation method for organic crystals according to any one of claims 1 to 9, or implement the screening method for organic crystals according to claim 10.

Images