Small molecule type selection method for direct-current cable accessory interface coating modifier

Abstract

The invention discloses a small molecule type selection method for a direct-current cable accessory interface coating modifier, which comprises the following steps of: calculating energy levels of a plurality of selected molecules through a quantum chemistry Gaussian simulation calculation method, and performing contrastive analysis; comprising the following steps: (1) opening Gauss View software, establishing a molecular structure of a small molecular substance, setting calculation parameters, and storing a file; (2) importing the file with the set calculation parameters into Gaussian software, and running a program after setting a path for storing a result file; (3) opening a chk result file operated by Gaussian, right-clicking Edit, and clicking Mos to see all energy level data of the small molecular substances; and (4) importing the result file into a Gauss Sum program to obtain a more visual molecular energy level orbital diagram.

Description

Technical Field

[0001] The invention belongs to the technical field of high voltage and insulation, and particularly relates to a method for selecting small molecules for a DC cable accessory interface coating modifier. Background Art

[0002] In recent years, with the continuous improvement of DC cable transmission power and capacity, the ability of interface coating agents to inhibit interface charge accumulation has decreased. Therefore, it is necessary to continuously promote the improvement of cable accessory interface coating materials. However, due to the wide variety of small molecule substances, it will take a lot of time and money to test them one by one, and the research on the modification of different substances is constantly deepening. The selection and modification mechanism of many added small molecules need more substantial verification. However, due to the relatively abstract interactions between different molecules, a certain spatial imagination is required. As the complexity of the molecular structure of the added substances increases, the difficulty of selection increases.

[0003] With the deepening of quantum chemistry research, chemical research has gradually entered the microscopic world, quantization theory has gradually matured, and with the improvement of computer technology, computational chemistry software has become more perfect. Among them, quantum chemistry Gaussian simulation calculation software is the mainstream quantum chemistry calculation software in the world because of its easy installation, low threshold for use, clear graphical interface, robust algorithm, high code efficiency and ability to meet most computing application requirements. It is widely used to predict the electronic structure and properties of molecules, molecular electrostatic potential scanning, infrared spectrum prediction, electronic energy level orbit calculation, atomic charge and potential, thermodynamic properties, chemical reaction mechanism and energy changes during the reaction process.

[0004] Gaussian software mainly includes Gaussian and Gauss View. Gaussian View is a 3D modeling software. Before using Gaussian software, you should first use Gaussian View to build a model of molecular structure, and then import the constructed structure input file into Gaussian software for calculation. After the calculation is completed, you can intuitively display the 3D graph of the molecular ground state, excited state and reaction transition state, as well as energy changes and other thermodynamic parameters. Gaussian software is used to optimize molecular structure and calculate molecular properties under various geometric structures. Summary of the invention

[0005] The purpose of the present invention is to overcome the difficulty in selecting existing small molecule substances and to provide a small molecule selection method for a DC cable accessory interface coating modifier.

[0006] The present invention provides a small molecule selection method for a DC cable accessory interface coating modifier, and calculates and compares the energy levels of multiple selected molecules through a quantum chemical Gaussian simulation calculation method.

[0007] The technical solution proposed by the present invention is to find the chemical structural formula of the selected small molecule substance, construct the molecular structure through Gauss View, and perform molecular optimization and calculation through Guassian. The method includes the following steps:

[0008] S1 is calculated by quantum chemical Gaussian simulation of small molecule substances coated with modifiers;

[0009] S2 uses quantum chemistry Gaussian simulation calculation to analyze the molecular energy level orbit of the selected small molecule;

[0010] S3 compares and analyzes the difference in energy level orbits between the coating agent with added small molecules and the original coating silicone oil;

[0011] S4 ranks the LUMO, HOMO and energy gap of small molecules, and finally selects the optimal small molecule for interface coating agent modification.

[0012] Furthermore, Gaussian simulation was used to calculate its molecular energy level orbital, and information including LUMO, HOMO, energy gap, and trap depth was obtained.

[0013] Furthermore, a DC cable interface coating agent modified small molecule substance containing different functional groups and branches is selected.

[0014] Further, the S4 is specifically as follows:

[0015] 1) After the molecular orbital simulation is completed, the LUMO, HOMO and energy gap data of the silicone oil matrix and the small molecule are compared;

[0016] 2) Sort the LUMO energy level data of small molecules;

[0017] 3) Sort the HUMO energy level data of small molecules;

[0018] 4) Sort the energy gaps of small molecules;

[0019] 5) After ranking LUMO, HOMO and energy gap, comprehensively compare the advantages and select the small molecule substance with the best overall data of the three.

[0020] The S1 is specifically as follows:

[0021] (1) Open Gauss View software and build a model based on the molecular structure diagram of the selected modifier;

[0022] (2) After the molecular model is built, right-click the mouse, select Calculte, and select Gaussian Calculate Setup;

[0023] (3) After the selection is completed, the setting page will appear. Select Opt+Freq in the Jop Type work type;

[0024] (4) In the Method section, only the second one is changed. Select DFT. In the Basis Set section, select 6-31G. Select d after the bracket that appears. The rest are the same as the initial settings.

[0025] (5) Title can be set according to your needs;

[0026] (6) In Link 0, select Specify for Memory Limit, set it to 1000, select MB for the unit, select Specify for Chkpoint File, and then select the desired save path;

[0027] (7) After the calculation settings are completed, close the settings interface, right-click the mouse, select File, and select Save;

[0028] (8) Open the Gaussian software, click File, click Open, and open the file with the previously set running parameters;

[0029] (9) Click RUN to set the result file save path. After the setting is completed, the software starts the calculation;

[0030] (10) After the software completes the calculation, a chk file will appear, which contains all the information required for the calculation;

[0031] (11) Click the chk file directly to display the optimized molecular structure. Right-click the mouse and select Edit.

[0032] Select Mos, and all energy level data of the molecular structure will appear;

[0033] (12) Open the Gauss Sum software, click File, and then click Open. This software can only process Output files.

[0034] (13) After opening the Output file, select Orbitals, select DOS, set the energy level range, click Creatoriginorbs.txt, and press Enter to display the line segment molecular energy level orbital diagram;

[0035] (14) The calculated molecular energy level orbitals can not only reveal the differences between the selected substances, which can be used for effective preliminary screening analysis, but also can compare the differences between the coating agent with the added small molecules and the original coating silicone oil, and analyze the mechanism of small molecule modification of the coating agent.

[0036] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0037] 1. There are many types of modified substances. After selecting them, the testing steps are complicated, time-consuming and costly. The workload can be greatly reduced by performing quantum chemical Gaussian calculations.

[0038] 2. The calculated molecular energy level orbits can not only show the differences between the selected substances, but also conduct effective preliminary screening analysis. In addition, the differences between the added small molecule coating agent and the original coating silicone oil can be compared, and the mechanism of small molecule modification of the coating agent can be analyzed.

[0039] 3. Draw a graph based on the molecular energy level orbital data. The graph can more intuitively show the characteristics of each small molecule energy level orbital.

[0040] 4. LUMO, HOMO, energy gap, electron affinity, ionization energy, trap depth, etc. can be seen from the molecular energy level orbital, and the corresponding data can be found for analysis according to research needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a molecular model diagram constructed by Gauss View;

[0042] Figure 2 It is the molecular energy level orbital distribution after Guassian optimization. DETAILED DESCRIPTION

[0043] The following is a further explanation of how the method for selecting small molecules for the interface coating modifier of DC cable accessories of the present invention is implemented in conjunction with the accompanying drawings and specific embodiments.

[0044] The purpose of the present invention is to provide a small molecule selection method for a DC cable accessory interface coating modifier, and to calculate and compare the energy levels of multiple selected molecules through a quantum chemical Gaussian simulation calculation method.

[0045] The specific implementation steps are as follows:

[0046] 1. Open Gauss View software and build the model according to the molecular structure diagram of the selected modifier;

[0047] 2. After the molecular model is built, right-click the mouse, select Calculte, and select Gaussian Calculate Setup;

[0048] 3. After the selection is completed, the setting page will appear. Select Opt+Freq in the Jop Type work type;

[0049] 4. In Method, only change the second one, select DFT, select 6-31G in Basis Set, select d in the first bracket, and follow the initial settings for the rest.

[0050] 5. Set the title according to your needs;

[0051] 6. In Link 0, select Specify for Memory Limit, set it to 1000, select MB for the unit, select Specify for Chkpoint File, and then select the desired save path;

[0052] 7. After the calculation settings are completed, close the settings interface, right-click the mouse, select File, and select Save;

[0053] 8. Open the Gaussian software, click File, click Open, and open the file with the previously set running parameters;

[0054] 9. Click RUN to set the result file save path. After the setting is completed, the software starts calculating;

[0055] 10. After the software completes the calculation, a chk file will appear, which contains all the information required for the calculation;

[0056] 11. Click the chk file directly to display the optimized molecular structure. Right-click the mouse, select Edit, and select Mos to display all the energy level data of the molecular structure.

[0057] 12. Open the Gauss Sum software, click File, and click Open. This software can only process Output files;

[0058] 13. After opening the Output file, select Orbitals, select DOS, set the energy level size range, click Creatoriginorbs.txt, and press Enter to display the line segment molecular energy level orbital diagram.

[0059] HOMO is the highest occupied molecular orbital energy level, LUMO is the lowest unoccupied molecular orbital energy level, and the energy gap is the difference between the LUMO energy level and the HOMO energy level. The LUMO energy level corresponds to the bottom energy level of the conduction band, the HOMO energy level corresponds to the top energy level of the valence band, and the energy gap is the bandgap width. HOMO has a looser binding force on electrons and has an electron-donating physique, while LUMO has a stronger affinity for electrons and has an electron-accepting physique. In the process of carrier transport inside a substance, electrons are easily captured by the LUMO orbital, and holes are easily captured by the HOMO orbital.

[0060] After completing the molecular energy level orbitals of the selected small molecule substances and silicone oil matrix, a comparative analysis is performed. The specific method is as follows:

[0061] 1. After the molecular orbital simulation is completed, compare the LUMO, HOMO and energy gap data of the silicone oil matrix and the small molecule;

[0062] 2. The smaller the LUMO energy level of a substance, the stronger its affinity for electrons, and the easier it is for electrons to adsorb on the substance. The simulation results show that the LUMO energy levels of the selected small molecule substances are all smaller than the silicone oil matrix. Therefore, when electrons enter the mixture, they will not affect the silicone oil matrix, which is beneficial to its insulation performance. The LUMO energy level data of small molecule substances are sorted;

[0063] 3. The larger the HUMO energy level of a substance, the stronger its affinity for holes, and holes are easily adsorbed on the substance. The HUMO energy levels of the selected small molecule substances are larger than the silicone oil matrix. Therefore, when holes enter, the holes will not affect the insulating properties of the silicone oil matrix. The HUMO energy level data of small molecule substances are sorted;

[0064] 4. The energy gap measures the ease with which a molecule is excited, that is, the smaller the energy gap, the easier it is for the molecule to be excited. When small molecules adsorb electrons and holes, they can release the energy adsorbed in the body in a radiation or non-radiation manner that is harmless to the silicone oil matrix after excitation, and return to the original unadsorbed state, and adsorb electrons and holes again. In theory, it ensures that small molecules are not consumable, and easy excitation also ensures the rapid action of this cycle, which is conducive to enhancing the protection effect of insulating materials. For this reason, we rank the energy gaps of small molecules;

[0065] 5. After ranking LUMO, HOMO and energy gap, comprehensively compare the advantages and select the small molecule substance with the best overall data of the three.

[0066] Specific comparison:

[0067]

[0068] LUMO: Dimethyl silicone oil > dimethyl benzophenone > 1,4-dihydroxybenzophenone > 2,4-dihydroxybenzophenone > chlorobenzophenone > difluorobenzophenone

[0069] HOMO: 1,4-dihydroxybenzophenone > 2,4-dihydroxybenzophenone > dimethylbenzophenone > chlorobenzophenone > difluorobenzophenone > dimethyl silicone oil

[0070] Band gap: dimethyl silicone oil > dimethyl benzophenone > chlorobenzophenone > difluorobenzophenone > 1,4-dihydroxybenzophenone > 2,4-dihydroxybenzophenone

[0071] Comparing the three data comprehensively, 2,4-dimethylbenzophenone has better performance.

Claims

1. A method for selecting small molecules for DC cable accessory interface coating modifiers, characterized in that: S1 is calculated by quantum chemical Gaussian simulation of small molecule substances coated with modifiers; S2 uses quantum chemistry Gaussian simulation calculation to analyze the molecular energy level orbit of the selected small molecule; S3 compares and analyzes the difference in energy level orbits between the coating agent with added small molecules and the original coating silicone oil; S4 ranks the LUMO, HOMO and energy gap of small molecules, and finally selects the optimal small molecule for interface coating agent modification.

2. The method for selecting small molecules for a DC cable accessory interface coating modifier according to claim 1, characterized in that: Gaussian simulation is used to calculate its molecular energy level orbital, and information including LUMO, HOMO, energy gap, and trap depth is obtained.

3. The method for selecting small molecules for a DC cable accessory interface coating modifier according to claim 1, characterized in that: Select small molecule substances containing different functional groups and branches to modify the DC cable interface coating agent.

4. The method for selecting small molecules for a DC cable accessory interface coating modifier according to claim 1, characterized in that: The S4 is specifically as follows: 1) After the molecular orbital simulation is completed, the LUMO, HOMO and energy gap data of the silicone oil matrix and the small molecule are compared; 2) Sort the LUMO energy level data of small molecules; 3) Sort the HUMO energy level data of small molecules; 4) Sort the energy gaps of small molecules; 5) After ranking LUMO, HOMO and energy gap, comprehensively compare the advantages and select the small molecule substance with the best overall data of the three.

5. The method for selecting small molecules for a DC cable accessory interface coating modifier according to claim 1, characterized in that: The S1 is specifically as follows: 1) Open Gauss View software and build a model based on the molecular structure diagram of the selected modifier; 2) After the molecular model is built, right-click the mouse, select Calculte, and select Gaussian Calculate Setup; 3) After the selection is completed, the setting page will appear. Select Opt+Freq in the Jop Type work type; 4) In Method, only change the second one, select DFT, select 6-31G in Basis Set, select d in the first bracket, and keep the rest as the initial settings; 5) Set the title according to your needs; 6) In Link 0, select Specify for Memory Limit, set it to 1000, select MB for the unit, select Specify for Chkpoint File, and then select the desired save path; 7) After the calculation settings are completed, close the settings interface, right-click the mouse, select File, and select Save; 8) Open Gaussian software, click File, click Open, and open the file with previously set running parameters; 9) Click RUN to set the result file save path. After the setting is completed, the software starts calculating; 10) After the software completes the calculation, a chk file will appear, which contains all the information required for the calculation; 11) Click the chk file directly to display the optimized molecular structure. Right-click the mouse, select Edit, and select Mos to display all the energy level data of the molecular structure. 12) Open the Gauss Sum software, click File, and click Open. This software can only process Output files. 13) After opening the Output file, select Orbitals, select DOS, set the energy level size range, click Creatoriginorbs.txt, and press Enter to display the line segment molecular energy level orbital diagram.

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