In search of a new SF₆alternative gas: cross-sections, transport coefficients and breakdown characteristics

SF₆ is one of the popular choices for gas-insulated applications. However, its global warming potential is very high and hence there is a need for an eco-friendly alternative [1]. A suitable alternative will have high ionization energy and high electronegativity. Further, to restrict the excitations, the orbital band gap needs to be high. Also, the liquefaction temperature should be low enough to maintain its gaseous state. To check the environmental impact, the gas should be non-toxic and its global warming potential (GWP) should be low. Further, the electron attachment capacity should be high. The dielectric strength and breakdown voltage should obviously be high to suit the insulation applications.

Our group is working on the search for eco-friendly gases for insulation applications, investigating the physiochemical properties, decomposition mechanism, and dielectric strength of the specie. In the talk, we will briefly present the target parameters of C₃F₆O which we propose as the new alternative gas. We will then discuss the main theme of our work where the electron impact cross sections and the transport coefficients are obtained. Based on these coefficients the dielectric strength and the breakdown voltage of the new gas are predicted. GAUSSIAN09 [2] is used for our quantum mechanical calculations of target parameters. The cross-section is obtained using R-matrix method via QUANTEMOL-EC software [3]. For the transport coefficients, BOLSIG+ code is utilized [4]. The breakdown voltage curve is obtained by fitting these coefficients [5].

[1] Tian S et al. 2020 AIP Advances, 10(5), 050702

[2] Frisch M J et al. 2009 Gaussian 09, Revision D. 01, Gaussian, Inc., Wallingford CT. See also: URL: http://www. gaussian. com.

[3] Cooper B et al. 2019 Atoms, 7(4), 97

[4] Hagelaar, G.J.M. and Pitchford, L.C., 2005 Plasma sources science and technology, 14(4), 722

[5] Radmilovic-Radjenovic M et al. 2021 Atmosphere, 12(4), 438