CN-122024876-A - Molecular dynamics simulation method for electron-induced gas desorption

CN122024876ACN 122024876 ACN122024876 ACN 122024876ACN-122024876-A

Abstract

The invention discloses a molecular dynamics simulation method for electron-induced gas desorption, which belongs to the technical field of molecular simulation, and comprises the steps of firstly constructing an alumina molecular model, then simulating the adsorption balance of hydrogen on the surface of alumina under different temperatures and air pressures by adopting a giant regular Monte Carlo method to obtain a stable adsorption configuration, then introducing explicit electron particles into an electron force field to simulate electron beam bombardment based on the configuration, simulating an electron-induced gas desorption dynamics process under a molecular dynamics frame, and finally quantitatively analyzing a desorption product. The invention realizes the continuous research from gas adsorption to electron induced desorption through the full atomic molecular dynamics simulation, overcomes the limitation that relevant experiments under high pressure are difficult to measure and difficult to reveal microscopic mechanism, and provides an effective simulation tool for deeply understanding the physical mechanism of gas desorption induced discharge on the dielectric surface.

Inventors

ZHANG JIANWEI
SUN HAIRONG
NIU YING
ZHANG RONGQI

Assignees

西安理工大学

Dates

Publication Date: 20260512
Application Date: 20260304

Claims (10)

1. The molecular dynamics simulation method for electron-induced gas desorption is characterized by comprising the following steps of: s1, constructing an alumina molecular model; s2, simulating the adsorption process of gas molecules on the surface of the alumina molecular model to obtain a stable adsorption model; S3, simulating an electron beam induced gas desorption process by adopting an explicit electronic force field based on a stable adsorption model.
2. The method according to claim 1, wherein the step S1 comprises: Selecting a standard alumina crystal structure; expanding the crystal structure to construct a three-dimensional model; the constructed model is exported as a data file readable by molecular dynamics simulation software.
3. The method according to claim 1, wherein the step S2 comprises: constructing a simulated cassette comprising an alumina substrate and a gas phase region; randomly generating gas molecules in the gas phase region; adopting a giant regular Monte Carlo method, and simulating the adsorption balance of gas molecules on the surface of the alumina under different preset temperatures and/or preset air pressures; a stable configuration to reach adsorption equilibrium was derived as a stable adsorption model.
4. A process according to claim 3, wherein in step S2 the gas molecule is hydrogen, and/or The adsorption process of the simulated gas molecules on the surface of the simulated gas molecules adopts the Lennard-Jones force field to describe the interatomic van der Waals interactions.
5. A method according to claim 3, wherein in step S2, the predetermined temperature is selected from at least one of 300K, 400K, 500K, and/or The preset air pressure is at least one selected from 1bar, 0.1bar, 0.01bar, 0.001bar, 0.0001bar and 10 -6 bar.
6. The method according to claim 1, wherein the step S3 comprises: Energy relaxation is carried out on the stable adsorption model, so that the system reaches a steady state; introducing an analog electron beam in the system, the electrons in the electron beam being arranged as explicit particles having a mass and an initial velocity; The interaction of electrons and an atomic system is described by adopting an electron force field, and the gas desorption dynamic process induced by electron bombardment is simulated.
7. The method according to claim 6, wherein the electrons in the electron force field are described by deformable Gaussian wave packets, and/or An effective nuclear potential is employed for the atoms in the alumina.
8. The method according to claim 6, wherein the energy of the electron beam is adjustable, and/or The electron beam is introduced into a predefined cylindrical space region at a set density.
9. The method according to any one of claims 1 to 8, further comprising step S4: and analyzing the simulation result data of the desorption process to obtain the time evolution and/or desorption yield of the desorption particle types and the desorption particle numbers.
10. The method according to claim 9, wherein the step S4 includes: and importing the track file which is output by simulation into visualization software for process observation and data analysis.

Description

Molecular dynamics simulation method for electron-induced gas desorption Technical Field The invention relates to the technical field of molecular simulation, in particular to a molecular dynamics simulation method for electron-induced gas desorption. Background In high-voltage vacuum electronic devices, gas adsorption and desorption on the surface of a dielectric medium are key factors for initiating early discharge and causing device failure, a large number of gas molecules are adsorbed on the surface of a dielectric medium material such as alumina in the process of device manufacture and operation, and when high voltage is applied or a local strong electric field exists, mechanisms such as Joule heat, electron bombardment and the like provide energy for adsorbing the gas to initiate rapid desorption of the gas. The instantaneously released gas forms high density gas cloud locally to lower the insulating strength obviously, and the desorbed gas molecule is easy to ionize in electric field to induce surface flashover or breakdown. At present, experiments for measuring gas adsorption/desorption are usually carried out under a high vacuum condition, and under a high pressure condition, although an electron induction effect still exists, experimental measurement often faces the problems of large signal interference, poor repeatability, difficulty in accurately detecting low-energy electrons and the like, so that a measurement result is unreliable, and a microcosmic mechanism of electron induction desorption cannot be accurately revealed. Therefore, a technical means capable of reliably researching the gas adsorption and electron-induced desorption processes from a microscopic scale under the complex conditions of high voltage, low energy electrons and the like is needed to understand the physical mechanism of the dielectric surface gas desorption induced discharge in depth. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a molecular dynamics simulation method for electron-induced gas desorption. In order to achieve the above purpose, the present invention provides the following technical solutions: the application provides a molecular dynamics simulation method for electron-induced gas desorption, which comprises the following steps: s1, constructing an alumina molecular model; s2, simulating the adsorption process of gas molecules on the surface of the alumina molecular model to obtain a stable adsorption model; S3, simulating an electron beam induced gas desorption process by adopting an explicit electronic force field based on a stable adsorption model. Further, the step S1 includes: Selecting a standard alumina crystal structure; expanding the crystal structure to construct a three-dimensional model; the constructed model is exported as a data file readable by molecular dynamics simulation software. Further, the step S2 includes: constructing a simulated cassette comprising an alumina substrate and a gas phase region; randomly generating gas molecules in the gas phase region; adopting a giant regular Monte Carlo method, and simulating the adsorption balance of gas molecules on the surface of the alumina under different preset temperatures and/or preset air pressures; a stable configuration to reach adsorption equilibrium was derived as a stable adsorption model. Further, in the step S2, the gas molecules are hydrogen gas, and/or The adsorption process of the simulated gas molecules on the surface of the simulated gas molecules adopts the Lennard-Jones force field to describe the interatomic van der Waals interactions. Further, in the step S2, the preset temperature is at least one selected from 300K, 400K and 500K, and/or The preset air pressure is at least one selected from 1bar, 0.1bar, 0.01bar, 0.001bar, 0.0001bar and 10 -6 bar. Further, the step S3 includes: Energy relaxation is carried out on the stable adsorption model, so that the system reaches a steady state; introducing an analog electron beam in the system, the electrons in the electron beam being arranged as explicit particles having a mass and an initial velocity; The interaction of electrons and an atomic system is described by adopting an electron force field, and the gas desorption dynamic process induced by electron bombardment is simulated. Further, the electron force field is an electron force field in which electrons are described by a deformable Gaussian wave packet, and/or An effective nuclear potential is employed for the atoms in the alumina. Further, the energy of the electron beam is adjustable, and/or The electron beam is introduced into a predefined cylindrical space region at a set density. Further, the method further comprises the step S4: and analyzing the simulation result data of the desorption process to obtain the time evolution and/or desorption yield of the desorption particle types and the desorption particle numbers. Further, the step S4 includes: and importing the tra