Mass spectrometric study of the dissociative ionization of sulphuryl fluoride by monoenergetic electron impact .1. Heteronuclear fragment ions

Abstract

The dissociative ionization of sulphuryl fluoride (SO2F2) under electron impact has been examined by using a trochoidal electron velocity selector and a magnetic sector mass spectrometer. The ionization efficiency curves of SO2F2+, SOF2+, SO2F+ and SOF+ have been recorded and the appearance energies of different electronic states of these ions were determined. The results were used to evaluate the dissociation energy D(OSF2-O)=5.32 eV, enthalpies of formation Delta H-f(SO2F)=-427.5 kJ/mol (-4.43eV), Delta H-f(SO2F+)=616 kJ/mol (6.39 eV), Delta H-f(SOF)=-207.5 kJ/mol (-2.15 eV), Delta H-f(SOF+)=710 kJ/mol (7.36 eV) and the ionization energies IE(SO2F)=10.82 eV and IE(SOF)=9.51 eV.