A method for designing layered furazan-based energetic material crystals
By screening, replacing, and optimizing crystal structure designs, the problem of rapid and accurate design of layered furazan-like energetic materials was solved, achieving a balance between high energy density and safety, and meeting the performance requirements of modern weapon systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAN MODERN CHEM RES INST
- Filing Date
- 2022-10-14
- Publication Date
- 2026-07-03
Smart Images
Figure HDA0003890790130000011 
Figure HDA0003890790130000012 
Figure HDA0003890790130000021
Abstract
Description
Technical Field
[0001] This invention relates to a method for designing energetic materials, and more particularly to a method for designing layered furazan-type energetic material crystals based on database search. Background Technology
[0002] Layered furazan-type energetic crystals refer to materials containing furazan structural units arranged in a layered structure within the crystal, exhibiting certain detonation properties. Due to their high enthalpy of formation and the presence of oxygen atoms, furazan rings are a crucial building block in the development of high-energy-density energetic materials. While there are well-known furazan-type energetic materials such as "BTF," "DDAF," and "DNTF," layered furazan-type energetic materials are relatively few in number.
[0003] With the continuous deployment of advanced weapon systems, the performance requirements for energetic materials have gradually shifted from a focus on high energy density to seeking superior overall energy and safety performance. Looking back at the nearly two-hundred-year history of modern energetic materials, while the research paradigm has evolved from the initial experimental "trial and error" approach to the current computationally-guided design, current computational guidance primarily assesses energetic material performance at the molecular scale, lacking performance prediction at the crystal scale.
[0004] Meanwhile, layered energetic materials, due to their slip-glide properties, are considered one of the development directions for low-sensitivity materials. However, due to the complexity of their molecular structures, existing methods struggle to accurately and quickly obtain the target crystal structure for the design of layered energetic materials. Summary of the Invention
[0005] To address the shortcomings or deficiencies of existing technologies, this invention provides a method for designing layered furazan-like energetic material crystals.
[0006] Therefore, the method provided by the present invention includes:
[0007] Step 1: Construct a basic crystal structure dataset. This dataset contains several material crystal structures. The chemical formulas of these material crystal structures contain furanone structures, do not contain elements other than C, H, O, and N, and have a material density greater than 1.6 g / cm³. 3 The molecular shape index is less than 0.005 and the packing orientation value is greater than 0.989; at the same time, all materials in the dataset have a common substructure, and the number of atoms in the common substructure is greater than 5.
[0008] Step 2: Perform crystal design for each material crystal structure in the basic crystal structure dataset. The crystal design includes replacing or adding atoms to other structures in the crystal structure other than the common substructure to improve the energy of the newly designed crystal structure.
[0009] Step 3: Optimize the crystal structures obtained in Step 2 using first-principles methods;
[0010] Step 4: Screening from the optimized crystal structures: The energy convergence must satisfy the condition that the energy change of each atom during the optimization process is less than 1 × 10⁻⁶. -7 eV and the force convergence satisfies that the change in the force value on each atom of the material during the optimization process is less than 1 / 2. Crystal structure;
[0011] Step 5: Calculate the phonon spectrum of each crystal structure selected in Step 4, and select crystal structures whose phonon spectrum does not contain imaginary frequencies or whose imaginary frequencies are less than 3.0 THz.
[0012] Step 6: Select crystal structures with a molecular shape index less than 0.005 and a packing orientation value greater than 0.989 from the crystal structures selected in Step 5.
[0013] Step 7: Calculate the detonation velocity of the crystal structures selected in Step 6, and select the final designed layered furazan-type energetic material crystal based on the magnitude of the detonation velocity.
[0014] Optionally, step 1 involves screening and constructing a basic crystal structure dataset in the Cambridge Crystal Structures database.
[0015] Furthermore, step 1 includes:
[0016] Step 11: Select the crystal structure of the material containing furazonium in its chemical structure;
[0017] Step 12: Screen the crystal structures selected in step 11 for materials whose chemical formulas do not contain elements other than C, H, O, and N.
[0018] Step 13: Among the materials selected in Step 12, screen for materials with a density greater than 1.6 g / cm³. 3 Crystal structure;
[0019] Step 14: Select crystal structures with a molecular shape index of less than 0.005 from the material crystal structures screened in Step 13;
[0020] Step 15: Select crystal structures with a packing orientation value greater than 0.989 from the crystal structures of the materials screened in Step 14;
[0021] Step 16: Identify all fragment structures with more than 5 atoms in each crystal structure screened in Step 15, among which the fragment structure with the most atoms is the common substructure.
[0022] Step 17: Select crystal structures with common substructures from the material crystal structures selected in step 15.
[0023] Optionally, in step 11, the Cambridge Crystal Database software ConQuest is used to search for crystal structures containing furazonium structures in the Cambridge Crystal Structure Database.
[0024] Optionally, in step 12, the chemical formula of the material is read in using Python, and the letter characters in the chemical formula are extracted using a regularization method to screen for crystal structures that do not contain elements other than C, H, O and N.
[0025] Optionally, the molecular shape index calculation method is as follows: extracting molecular coordinate information from the crystal structure using API commands from the Cambridge Crystal Structures database; and calculating the molecular shape index based on the molecular coordinate information.
[0026] Optionally, the crystal packing orientation value is calculated as follows: using the API commands of the Cambridge Crystal Database to extract molecular coordinate information and adjacent molecular coordinate information in the crystal structure; and calculating the crystal packing orientation value based on the molecular coordinate information and adjacent molecular coordinate information.
[0027] Optionally, the common substructure search method is as follows: obtain the Smiles code of each crystal structure from the Cambridge Crystal Database index number; use Python programming to read in the Smiles code of each crystal structure, identify all fragment structures with more than 5 atoms in the crystal structure, and record them in the Python dictionary container dict(), where the fragment structure with the most numbers in the dictionary is the common substructure.
[0028] Optionally, the crystal design method is as follows: import the material crystal structure data file into the Materials Studio software; replace or add atoms to other structures in the crystal besides the molecular common substructure.
[0029] Optionally, the detonation performance data of the crystal structures screened in step 5 can be calculated using the KJ equation.
[0030] Furthermore, crystal structures with detonation velocities greater than 8000 m / s or the highest detonation velocities can be selected as the designed layered furazan-type energetic material crystals.
[0031] This invention anchors the intercrystalline interaction units of layered furazan-like energetic materials, ensuring that the effects on the formation of the layered structure remain unchanged. Then, the molecules in the original crystal structure are replaced and atoms are added to increase the energy level. The structure is optimized using first-principles methods, and the detonation performance of the designed material is evaluated using the KJ equation. The design concept and calculation process of this method are simple and fast. Attached Figure Description
[0032] Figure 1The examples of layered furazan-like energetic materials selected in the embodiments of the present invention are shown below each molecular formula, and the English abbreviations below each molecular formula are the index numbers of the corresponding materials.
[0033] Figure 2 This is an example of a shared substructure for layered furazan-type energetic materials in this invention.
[0034] Figure 3 Examples D1-D3 show the newly designed crystal structures and corresponding molecular structures in the embodiments of the present invention;
[0035] Figure 4 Examples D4 and D5 show the newly designed crystal structures and corresponding molecular structures in this embodiment of the invention.
[0036] Figure 5 The molecular structure diagram of layered furazan-based energetic material D1 designed in the embodiments of the present invention is shown.
[0037] Figure 6 This is a molecular structure diagram of the layered furazan-based energetic material D2 designed in an embodiment of the present invention;
[0038] Figure 7 This is a crystal structure diagram of the layered furazan-based energetic material D1 designed in an embodiment of the present invention;
[0039] Figure 8 This is a crystal structure diagram of the layered furazan-based energetic material D2 designed in an embodiment of the present invention;
[0040] Figure 9 The three example materials and the reference material TATB (1,3,5-triamino-2,4,6-trinitrobenzene, a typical layered energetic material) selected in the embodiments of the present invention are included in the index number (ID), molecular structure, and molecular shape index (SI).
[0041] Figure 10 These are two examples of materials that meet the molecular shape index screening criteria in this invention, including index number (ID), molecular structure, and packing orientation value (PO). Detailed Implementation
[0042] Unless otherwise specified, the scientific and technical terms used in this article are intended for understanding by those skilled in the art.
[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to embodiments. These embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.
[0044] Materials databases containing parameters involved in the methods of this invention (such as the Cambridge Analytic Database) can serve as the basic data for this invention. To better understand this invention, the Cambridge Analytic Database is selected as the data source for the following embodiments. As a well-known database in the field, the Cambridge Analytic Database contains all recognized crystal structures of organic compounds worldwide. This database obtains reliable data from recognized reports, ensuring the accuracy of subsequent research; furthermore, the database contains a large amount of data, including more than 10... 6 The data includes information on the molecular structure of the crystal, as well as information such as crystal density and chemical formula.
[0045] Example:
[0046] The Cambridge Crystal Structure Database was then used for screening in steps 11-15 to obtain... Figure 1 The material meets the following conditions: "The chemical formula of the crystal structure contains furanone structure, the chemical formula does not contain elements other than C, H, O and N, and the material density is greater than 1.6 g / cm³". 3 Twelve material molecular structures with a molecular shape index less than 0.005 and a packing orientation value greater than 0.989 were further screened. From these 12 material molecular structures, those with… Figure 2 The material molecules shown have common substructures, including materials with the number HIZHII in the Cambridge Crystal Structures database;
[0047] Next, crystal design was performed on the selected material molecules. Specifically, the largest common substructure of the material was fixed, and atoms were replaced or added to other molecular structures within the crystal to increase the energy of the newly designed crystal structure; in order to remove HIZHII Figure 2 Taking the remaining part of the shared substructure, namely the six-membered ring in the middle, as an example of replacing and adding atoms, considering the characteristics of energetic materials (elements) and increasing energy, one approach is to replace the oxygen atom in the six-membered ring with a nitrogen atom to increase the enthalpy of formation; another approach is to add an oxygen atom to the nitrogen atom on the six-membered ring, i.e., N-oxidation.
[0048] See Figure 3 and 4As shown, the crystal structures and corresponding molecular structures designed in this embodiment are given, namely D1-D5. Then, the crystal structures involved are optimized using first-principles methods, and submitted for screening as described in step 4. The optimized structures of molecules shown in D1-D5 all satisfy the conditions of step 4. Further screening is performed using the conditions shown in step 5. The imaginary frequency of the molecular structure corresponding to D1 is 0.0078 THz, the imaginary frequency of the molecular structure corresponding to D2 is 0.18 THz, the imaginary frequency of the molecular structure corresponding to D4 is 2.4 THz, and the imaginary frequencies of the molecular structures corresponding to D3 and D5 are both greater than 3.0 THz (considered unstable). Therefore, in this example, only the crystal designs of D1, D2, and D4 are retained for subsequent screening.
[0049] Further screening was then conducted, and the molecular shape index of the molecule corresponding to D1 was 0.0001, the molecular shape index of the molecule corresponding to D2 was 0.0003, and the molecular shape index of the molecule corresponding to D4 was 0.004. All of these were less than the molecular shape screening standard of 0.005, so they were retained for the next step of screening.
[0050] The crystal packing orientation value of the molecule corresponding to D1 is 0.996 (>0.989), the crystal packing orientation value of the molecule corresponding to D2 is 0.992 (>0.989), and the crystal packing orientation value of the molecule corresponding to D4 is 0.975 (<0.989). Therefore, D1 and D2 meet the screening criteria for packing orientation value, and D4 is screened out.
[0051] Next, the KJ equation was used to calculate the detonation performance data corresponding to D1 and D2; the detonation performance of both D1 and D2 is above 8000 m / s, with D2 reaching 8400 m / s. Thus, this embodiment yields two layered furzanol energetic crystals, D1 and D2, whose molecular structures are described in [reference needed]. Figure 5 , Figure 6 For crystal structures, please refer to [reference]. Figure 7 , Figure 8 .
[0052] It should be further noted that searching for materials containing furazan structures and retrieving the crystal counts in the Cambridge Crystal Structures database is achieved using relevant software, the index numbers of each material in the database, and existing programs, based on the characteristics of the Cambridge Crystal Structures database itself. This allows for the processing of large amounts of data (e.g., more than 10) in a relatively short time. 6 The data is processed, filtered, and designed effectively. For example, the Cambridge Crystal Database software ConQuest is used to search for crystal structures containing furazans; the Cambridge Crystal Database API program is used to read the material database index number, material chemical formula, and density.
[0053] More specifically, in this invention, the element screening of materials can be achieved by reading the chemical formula of a specific material (in string format) and using a regularized string expression program written in Python to extract element symbols from the chemical formula. If the chemical formula of a material does not contain elements other than C, H, O, and N, the database index number of the material is recorded, and the next screening step is performed. If the chemical formula of a material contains elements other than C, H, O, and N, the material is discarded, and the next material is screened. The index number can also be used to record and identify the corresponding materials during the screening process for other indicators.
[0054] The calculation of the molecular shape index can be performed using API commands from the Cambridge Crystal Database to extract molecular coordinate information from the crystal structure of the material; based on the molecular coordinate information, the molecular shape index is calculated (see [reference needed]). Figure 9 The figure illustrates the molecular shape indices of four structures from the Cambridge Crystal Structures database.
[0055] The calculation of packing orientation values can be performed using API commands from the Cambridge Crystal Database to extract molecular coordinates and adjacent molecular coordinates from the crystal structure; based on the molecular coordinates and adjacent molecular coordinates, the crystal packing orientation values can be calculated. (See [link to relevant documentation]). Figure 10 The figure shows the crystal packing orientation values of two materials from the Cambridge Crystal Structures database.
[0056] The selection of common substructures can be achieved by obtaining the Smiles code of the corresponding material based on the index number in the Cambridge Crystal Structures database. The material's Smiles code is then read in using Python programming, and all fragment structures with more than 5 atoms in the material are identified and recorded in the Python dictionary container dict(). The fragment structure with the most occurrences in this dictionary is the common substructure.
[0057] Crystal design can be achieved by downloading the crystal structure data file of the corresponding material from the Cambridge Crystal Structure Database using the Cambridge Crystal Structure Database index number; importing the downloaded crystal structure data file into the Materials Studio software; then fixing the common substructures in the material molecules, replacing or adding atoms to other structures; and finally exporting the designed crystal structure data file.
[0058] For crystal structure optimization, first-principles methods are used; for example, VASP software can be used for crystal structure optimization.
[0059] It should also be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.
Claims
1. A method for designing layered furazan-like energetic material crystals, characterized in that, The methods include: Step 1: Construct a basic crystal structure dataset. This dataset contains several material crystal structures. The chemical formulas of these crystal structures contain furanone structures, do not contain elements other than C, H, O, and N, and have a density greater than 1.6 g / cm³. 3 The molecular shape index is less than 0.005 and the packing orientation value is greater than 0.989; at the same time, all materials in the dataset have a common substructure, and the number of atoms in the common substructure is greater than 5. Step 2: Perform crystal design for each material crystal structure in the basic crystal structure dataset. The crystal design includes replacing or adding atoms to other structures in the crystal structure other than the common substructure to improve the energy of the newly designed crystal structure. Step 3: Optimize the crystal structures obtained in Step 2 using first-principles methods; Step 4: Screening from the optimized crystal structures: The energy convergence must satisfy the condition that the energy change of each atom during the optimization process is less than 1 × 10⁻⁶. -7 eV and the force convergence satisfies that the change in the force value on each atom of the material during the optimization process is less than 1×10. -3 Crystal structure at eV / Å; Step 5: Calculate the phonon spectrum of each crystal structure selected in Step 4, and select crystal structures whose phonon spectrum does not contain imaginary frequencies or whose imaginary frequencies are less than 3.0 THz. Step 6: Select crystal structures with a molecular shape index less than 0.005 and a packing orientation value greater than 0.989 from the crystal structures selected in Step 5. Step 7: Calculate the detonation velocity of the crystal structures selected in Step 6, and select the final designed layered furazan-type energetic material crystal based on the magnitude of the detonation velocity.
2. The method for designing layered furazan-type energetic material crystals as described in claim 1, characterized in that, Step 1: Select and construct a basic crystal structure dataset from the Cambridge Crystal Structures Database.
3. The method for designing layered furazan-type energetic material crystals as described in claim 2, characterized in that, Step 1 includes: Step 11: Select the crystal structure of the material containing furazonium in its chemical structure; Step 12: Screen the crystal structures selected in step 11 for materials whose chemical formulas do not contain elements other than C, H, O, and N. Step 13: Among the materials selected in Step 12, select those with a density greater than 1.6 g / cm³. 3 Crystal structure; Step 14: Select crystal structures with a molecular shape index of less than 0.005 from the material crystal structures screened in Step 13; Step 15: Select crystal structures with a packing orientation value greater than 0.989 from the crystal structures of the materials screened in Step 14; Step 16: Identify all crystal fragments with more than 5 atoms selected in Step 15. The most numerous segment structure is the common substructure; crystal structures with common substructures are selected from the material crystal structures screened in step 15.
4. The method for designing layered furazan-type energetic material crystals as described in claim 3, characterized in that, In step 11, the Cambridge Crystal Database software ConQuest is used to search for crystal structures containing furanone structures in the Cambridge Crystal Structure Database.
5. The method for designing layered furazan-type energetic material crystals as described in claim 3, characterized in that, Step 12 uses Python to read the chemical formula of the material and uses a regularization method to extract letter characters from the chemical formula to screen for crystal structures that do not contain elements other than C, H, O and N.
6. The method for designing layered furazan-type energetic material crystals as described in claim 3, characterized in that, The molecular shape index calculation method is as follows: extract molecular coordinate information from the crystal structure using API commands from the Cambridge Crystal Structures database; and calculate the molecular shape index based on the molecular coordinate information.
7. The method for designing layered furazan-type energetic material crystals as described in claim 3, characterized in that, The method for calculating the crystal packing orientation value is as follows: using the API commands of the Cambridge Crystal Database to extract molecular coordinate information and adjacent molecular coordinate information in the crystal structure; and calculating the crystal packing orientation value based on the molecular coordinate information and adjacent molecular coordinate information.
8. The method for designing layered furazan-type energetic material crystals as described in claim 3, characterized in that, The common substructure search method is as follows: obtain the Smiles code of each crystal structure from the Cambridge Crystal Database index number; use Python programming to read in the Smiles code of each crystal structure, identify all fragment structures with more than 5 atoms in the crystal structure, and record them in the Python dictionary container dict(). The fragment structure with the most numbers in this dictionary is the common substructure.
9. The method for designing layered furazan-type energetic material crystals as described in claim 3, characterized in that, The crystal design method is as follows: read the material crystal structure data file into the Materials Studio software; replace or add atoms to other structures in the crystal besides the common molecular substructure.
10. The method for designing layered furazan-type energetic material crystals as described in claim 1, characterized in that, The detonation performance data of the crystal structures screened in step 6 were calculated using the KJ equation.
11. The method for designing layered furazan-type energetic material crystals as described in claim 1, characterized in that, Crystal structures with detonation velocities greater than 8000 m / s or the highest detonation velocities were selected as the designed layered furazan-type energetic material crystals.