Excitation and fragmentation of the dielectric gas C4F7N: Electrons vs photons

0567951 - ÚFCH JH 2024 RIV US eng J - Journal Article
Ovád, T. - Sapunar, M. - Sršeň, Š. - Slavíček, P. - Mašín, Z. - Jones, Nykola C. - Hoffmann, S. V. - Ranković, Miloš - Fedor, Juraj
Excitation and fragmentation of the dielectric gas C4F7N: Electrons vs photons.
Journal of Chemical Physics. Roč. 158, č. 1 (2023), č. článku 014303. ISSN 0021-9606. E-ISSN 1089-7690
R&D Projects: GA ČR(CZ) GX21-26601X; GA TA ČR(CZ) TK04020069
Institutional support: RVO:61388955
Keywords : Absorption spectroscopy * Dissociation * Electron energy levels
OECD category: Physical chemistry
Impact factor: 4.4, year: 2022
Method of publishing: Open access

C4F7N is a promising candidate for the replacement of sulfur hexafluoride as an insulating medium, and it is important to understand the chemical changes initiated in the molecule by collision with free electrons, specifically the formation of neutral fragments. The first step of neutral fragmentation is electronic excitation, yet neither the absorption spectrum in the vacuum ultraviolet (VUV) region nor the electron energy loss spectrum have previously been reported. Here, we experimentally probed the excited states by VUV photoabsorption spectroscopy and electron energy loss spectroscopy (EELS). We found that the distribution of states populated upon electron impact with low-energy electrons is significantly different from that following photoabsorption. This difference was confirmed and interpreted with ab initio modeling of both VUV and EELS spectra. We propose here a new computational protocol for the simulation of EELS spectra combining the Born approximation with approximate forms of correlated wave functions, which allows us to calculate the (usually very expensive) scattering cross sections at a cost similar to the calculation of oscillator strengths. Finally, we perform semi-classical non-adiabatic dynamics simulations to investigate the possible neutral fragments of the molecule formed through electron-induced neutral dissociation. We show that the product distribution is highly non-statistical.
Permanent Link: https://hdl.handle.net/11104/0339258