Fragment appearance energies in dissociative ionization of a sulfur hexafluoride molecule by electron impact

Theoretical analysis of the fragment appearance energies corresponding to possible channels of formation of SF$_k^+$ fragments in dissociative ionization of the SF$_6$ molecule by an electron impact is carried out. The total energies of neutral and ion molecular and atomic fragments are calculated using the theoretical methods of the GAMESS program complex. It is concluded that apart from dissociative ionization via autoionizing repulsive electronic states of the SF$_6$ molecule, the excitation channels for SF$_k^+$ fragments and F$_2$ molecules play a significant role, which leads to higher values of the observed fragment appearance energy as compared to theoretical values. The dependence of the energy corresponding to the formation of SF$_k^+$ c fragments on the number $k$ of fluorine atoms is considered.