Theoretical calculation of total electron-impact ionization cross section of C6F12O

Yang Wang,Guozhi Zhang,Yufei Wang,Xiaoxing Zhang,Wei Liu,Shuangshuang Tian

doi:10.1063/1.5133830

Abstract

C6F12O can be used in gas-insulated equipment due to its excellent insulation properties. The purpose of this paper is to calculate the total electron-impact ionization cross section to evaluate the dielectric strength of the molecule using the Deutsch–Märk formula. First, according to the calculation method of quantum chemistry, the structure of the molecule is optimized. Three different methods, such as Mulliken population analysis, C-squared population analysis, and natural atomic orbital (NAO), are used to calculate the molecular orbital components, and then the molecular collision cross section is obtained. The influence of different weighting factors on the calculation results is analyzed. The validity of the proposed method is verified by the calculation results of H2O, C3H6O, and C5F10O. The results show that the calculation value with the NAO method is closer to the experimental results, which provides a reference for the calculation and analysis of the collision cross section of C6F12O. The calculation results in this paper can provide basic data for further calculation of the dielectric strength of C6F12O.

Highlights

SF6 is widely used in electrical equipment such as gas insulated switchgear (GIS), gas insulated transmission line (GIL), gas insulation transformers (GIT), and other gas insulated equipment
The total cross section of electron-impact ionization of C6F12O molecules is calculated by the DM formula
In the calculation of the atomic orbital composition of the molecule, two different methods, the addition base function and the natural atomic orbital (NAO), are used and the basis function distribution is based on Mulliken population analysis (MPA) and SCPA

Summary

Introduction

SF6 is widely used in electrical equipment such as gas insulated switchgear (GIS), gas insulated transmission line (GIL), gas insulation transformers (GIT), and other gas insulated equipment. C6F12O is a non-flammable material that is harmless to the environment. It was originally used as a fire extinguishing agent to replace the halon series to reduce the damage to the ozone layer.[6]. The breakdown products and thermal decompositions are mainly fluorocarbons, such as CF4, C2F6, and C3F8. These gases are all alternative gases with better insulation properties and have a smaller impact on the environment than SF6.8–10 These studies have initially shown that C6F12O mixtures have the potential to be used as gas insulating media in electrical equipment, especially in medium and low voltage equipment

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