A method for constructing a layered rotor phase based on analog computation

Abstract

The application is a method for constructing a layered rotor phase based on analog calculation, belongs to the technical field of theoretical calculation, and is used for analogically obtaining a rotor phase with a layered structure. The method comprises the following steps: constructing an isotropic liquid phase model, setting a vacuum layer for the liquid phase model, performing liquid-solid transformation simulation on the liquid phase model with the vacuum layer to obtain a solid phase system with a layered structure; and performing calculation and processing (including screening out defective molecules, calculating correction coefficients, calculating the single-molecule area of the molecules perpendicular to the long axis and correcting, etc.) on the atomic coordinate information of each molecule in the system at different temperatures to determine the temperature range of the rotor phase in the solid phase temperature range, and finally obtain the rotor phase with the layered structure. The application provides a simple and effective method for constructing the rotor phase with the layered structure, and has important significance for the basic theoretical research of the rotor phase, especially for exploring the influence of the layered structure on the formation process of the rotor phase.

Description

Technical Field

[0001] This invention relates to the field of theoretical calculation, and more specifically to a method for constructing layered rotor phases based on simulation calculation. Background Technology

[0002] Rotor phases are a series of special condensed phases intermediate between isotropic liquid phases and ordered crystalline phases, widely found in long alkyl compounds. Currently reported rotor phases include RI (orthorhombic), RII (hexagonal), RIII (triclinic), RIV (monoclinic), and RV (monoclinic). Although rotor phases share similar lattice structures with crystalline phases, they exhibit lower density and higher molecular mobility compared to crystalline phases. Previous research on rotor phases has largely focused on phase types, phase transition sequences, and thermodynamic and kinetic phase behavior—fields primarily in physics or physicochemical fields. In recent years, research on rotor phases has gradually expanded into the chemical field, investigating the chemical reactions and photopolymerization behavior of molecules within rotor phases. However, the fundamental theoretical research on rotor phases is still incomplete, and the formation mechanisms of rotor phases remain unexplained, which significantly limits the development of rotor phase systems.

[0003] Since rotor phases often exist in a layered stacking form, and reports indicate that interlayer interactions have a significant impact on rotor phase behavior, research on the layered structure of rotor phases, such as simulating the formation process, interlayer arrangement rules, and interlayer molecular interaction modes, is of great importance for understanding the formation process of rotor phases. However, traditional liquid-solid simulation methods often yield disordered solid phase structures, making it difficult to achieve highly ordered layered arrangements. Therefore, developing simulation methods for layered rotor phases is essential.

[0004] Therefore, this invention proposes a method for constructing layered rotor phases based on computational simulation. This method is simple and efficient, and is of great significance for further research on the influence of layered structures on the rotor phase formation process. Summary of the Invention

[0005] The purpose of this invention is to establish a method for constructing layered rotor phases based on computational simulation.

[0006] To achieve the above objectives, the technical solution adopted by the present invention includes the following steps:

[0007] (1) Based on molecular dynamics, a liquid phase model of the molecule is constructed. A vacuum layer of a certain thickness is set along the z-axis of the three-dimensional Cartesian coordinate system. The system with the vacuum layer is structurally optimized to eliminate unreasonable structures. Then, it is cooled at a certain rate. A frame of structure (containing atomic coordinate information) is read every 1-2K for subsequent analysis.

[0008] (2) Calculate the orientation of the molecular long axis using structural information, obtain the angle θ between it and the z-axis, remove molecules with θ > 10°, and average the θ values ​​of the remaining molecules to obtain θ. av And use this to calculate the correction coefficient δ=cos(θ) av );

[0009] (3) Count the number of molecules n in each layer, and combine this with the dimensions of the simulation system along the x and y axes (x_box and y_box), calculate the monomolecular area of ​​each layer perpendicular to the major axis, and correct for A. corr =δ*[(x_box*y_box) / n], averaging the calculation results for each layer, to obtain the average area A of the system molecules perpendicular to the major axis. av This allows for the determination of the rotor phase temperature range (19.0°C) within the solid-state temperature range. av <20.0 is the rotor phase), and finally a rotor phase with a layered structure is obtained. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0011] Example 1

[0012] A random system of 300 1-hexadecene molecules was constructed using Packmol software as the initial simulation model. First, the system was heated to its liquidus temperature and equilibrated for 5 ns to obtain a completely disordered liquid-phase model. Then, a vacuum layer was added along the z-axis of the model, with a thickness 1.0 times the z-axis dimension of the liquid-phase model. Next, the system was cooled at a rate of 1 K / ns, and the structure file was read every 2 K. The orientation of the molecular long axis was calculated using the structural information, yielding the angle θ between the long axis and the z-axis. Molecules with θ > 10° were removed, and the average θ value of the remaining molecules was used to calculate the correction factor δ = 0.9953. Using the number of molecules in each layer, the dimensions of the system along the x and y axes, and the correction factor, the average area of ​​the system molecules perpendicular to the long axis at different temperatures was calculated. Combined with the criteria for determining the rotor phase, the temperature range for the layered rotor phase of the system was determined to be 275–303 K.

[0013] Example 2

[0014] ​A random system of 300 1-hexadecene molecules was constructed using Packmol software as the initial simulation model. First, the system was heated to its liquidus temperature and equilibrated for 5 ns to obtain a completely disordered liquid-phase model. Then, a vacuum layer with a thickness 1.5 times the z-axis dimension of the liquid-phase model was added to the model. Next, the system was cooled at a rate of 1 K / ns, with the structure file read every 2 K. The orientation of the molecular long axis was calculated using the structural information, yielding the angle θ between the long axis and the z-axis. Molecules with θ > 10° were removed, and the average θ value of the remaining molecules was used to calculate the correction factor δ = 0.9986. Using the number of molecules in each layer, the system dimensions along the x and y axes, and the correction factor, the average area of ​​the system molecules perpendicular to the long axis at different temperatures was calculated. Combined with the criteria for determining the rotor phase, the temperature range for the layered rotor phase was determined to be 273–299 K.

[0015] Example 2

[0016] A random system of 600 1-hexadecene molecules was constructed using Packmol software as the initial simulation model. First, the system was heated to its liquidus temperature and equilibrated for 5 ns to obtain a completely disordered liquid-phase model. Then, a vacuum layer was added along the z-axis of the model, with a thickness 1.2 times the z-axis dimension of the liquid-phase model. Next, the system was cooled at a rate of 5 K / ns, with the structure file read every 2 K. The orientation of the molecular long axis was calculated using the structural information, yielding the angle θ between the long axis and the z-axis. Molecules with θ > 10° were removed, and the average θ value of the remaining molecules was used to calculate the correction factor δ = 0.9847. Using the number of molecules in each layer, the dimensions of the system along the x and y axes, and the correction factor, the average area of ​​the system molecules perpendicular to the long axis at different temperatures was calculated. Combined with the criteria for determining the rotor phase, the temperature range for the layered rotor phase of the system was determined to be 281–317 K.

[0017] Example 4

[0018] A random system of 150 n-tetradecane molecules was constructed using Packmol software as the initial simulation model. First, the system was heated to its liquidus temperature and equilibrated for 5 ns to obtain a completely disordered liquid-phase model. Then, a vacuum layer was added along the z-axis of the model, with a thickness 1.0 times the z-axis dimension of the liquid-phase model. Next, the system was cooled at a rate of 0.1 K / ns, with the structure file read every 2 K. The orientation of the molecular long axis was calculated using the structural information, yielding the angle θ with the z-axis. Molecules with θ > 10° were removed, and the average θ value of the remaining molecules was used to calculate the correction factor δ = 0.9807. Using the number of molecules in each layer, the dimensions of the system along the x and y axes, and the correction factor, the average area of ​​the system molecules perpendicular to the long axis at different temperatures was calculated. Combined with the criteria for determining the rotor phase, the temperature range for the layered rotor phase of the system was determined to be 335–347 K.

[0019] Example 5

[0020] A random system of 200 n-docosahexanes was constructed using Packmol software as the initial simulation model. First, the system was heated to its liquidus temperature and equilibrated for 5 ns to obtain a completely disordered liquid-phase model. Then, a vacuum layer was added along the z-axis of the model, with a thickness 0.5 times the z-axis dimension of the liquid-phase model. Next, the system was cooled at a rate of 1 K / ns, with the structure file read every 1 K. The orientation of the molecular long axis was calculated using the structural information, yielding the angle θ between the long axis and the z-axis. Molecules with θ > 10° were removed, and the average θ value of the remaining molecules was used to calculate the correction factor δ = 0.9913. Using the number of molecules in each layer, the dimensions of the system along the x and y axes, and the correction factor, the average area of ​​the system molecules perpendicular to the long axis at different temperatures was calculated. Combined with the criteria for determining the rotor phase, the temperature range for the layered rotor phase of the system was determined to be 332-345 K.

[0021] Example 6

[0022] A random system of 900 n-tetane molecules was constructed using Packmol software as the initial simulation model. First, the system was heated to its liquidus temperature and equilibrated for 5 ns to obtain a completely disordered liquid-phase model. Then, a vacuum layer was added along the z-axis of the model, with a thickness 1.0 times the z-axis dimension of the liquid-phase model. Next, the system was cooled at a rate of 2 K / ns, with the structure file read every 2 K. The orientation of the molecular long axis was calculated using the structural information, yielding the angle θ between the long axis and the z-axis. Molecules with θ > 10° were removed, and the average θ value of the remaining molecules was used to calculate the correction factor δ = 0.9972. Using the number of molecules in each layer, the dimensions of the system along the x and y axes, and the correction factor, the average area of ​​the system molecules perpendicular to the long axis at different temperatures was calculated. Combined with the criteria for determining the rotor phase, the temperature range for the layered rotor phase of the system was determined to be 279–295 K.

[0023] Example 7

[0024] A random system of 1200 n-tetane molecules was constructed using Packmol software as the initial simulation model. First, the system was heated to its liquidus temperature and equilibrated for 5 ns to obtain a completely disordered liquid-phase model. Then, a vacuum layer with a thickness 1.2 times the z-axis dimension of the liquid-phase model was added to the model. Next, the system was cooled at a rate of 10 K / ns, with the structure file read every 2 K. The orientation of the molecular long axis was calculated using the structural information, yielding the angle θ between the long axis and the z-axis. Molecules with θ > 10° were removed, and the average θ value of the remaining molecules was used to calculate the correction factor δ = 0.9947. Using the number of molecules in each layer, the dimensions of the system along the x and y axes, and the correction factor, the average area of ​​the system molecules perpendicular to the long axis at different temperatures was calculated. Combined with the criteria for determining the rotor phase, the temperature range for the layered rotor phase of the system was determined to be 283–291 K.

[0025] Example 8

[0026] A random system of 600 octadecyl acrylate molecules was constructed using Packmol software as the initial simulation model. First, the system was heated to its liquidus temperature and equilibrated for 5 ns to obtain a completely disordered liquid-phase model. Then, a vacuum layer was added along the z-axis of the model, with a thickness 1.0 times the z-axis dimension of the liquid-phase model. Next, the system was cooled at a rate of 2 K / ns, with the structure file read every 2 K. The orientation of the molecular long axis was calculated using the structural information, yielding the angle θ with the z-axis. Molecules with θ > 10° were removed, and the average θ value of the remaining molecules was used to calculate the correction factor δ = 0.9966. Using the number of molecules in each layer, the dimensions of the system along the x and y axes, and the correction factor, the average area of ​​the system molecules perpendicular to the long axis at different temperatures was calculated. Combined with the criteria for determining the rotor phase, the temperature range for the layered rotor phase of the system was determined to be 323-329 K.

Claims

1. A method for constructing layered rotor phases based on simulation calculations, characterized in that... Includes the following steps: (1) Constructing a liquid-phase model of molecules based on molecular dynamics, and applying the liquid-phase model along a three-dimensional Cartesian coordinate system. z A vacuum layer of a certain thickness is set along the axis. After the system with the vacuum layer is structurally optimized to eliminate unreasonable structures, it is cooled at a certain rate. A frame of atomic coordinate information is read every 1~2 K for subsequent analysis. (2) Calculate the orientation direction of the molecular long axis using structural information, and obtain its relationship with... z Angle between axes θ Remove θ Molecules with a velocity greater than 10° affect the remaining molecules. θ The average value is obtained θ av And use this to calculate the correction factor. δ =cos( θ av ); (3) Count the number of molecules in each layer n Combined with the simulation system along x The dimension of the direction is x_box and y The dimension in the axial direction is y_ box Calculate and correct the monomolecular area of ​​each layer of molecules perpendicular to the long axis. A corr = δ* [( x_box * y_box ) / n The calculation results for each layer are averaged to obtain the average area of ​​the system molecules perpendicular to the major axis. A av This allows for the determination of the rotor phase temperature range within the solid-state temperature range, ultimately yielding a rotor phase with a layered structure; where 19.0 < A av <20.0 indicates the rotor phase.

2. The method for constructing layered rotor phases based on simulation calculation according to claim 1, characterized in that: In step (1), the thickness of the vacuum layer is along the liquid phase model. z 0.1 to 2 times the axial dimension.

3. The method for constructing layered rotor phases based on simulation calculation according to claim 1, characterized in that: The cooling rate in step (1) is 0.01~10 K / ns.