AN ELECTRON IMPACT STUDY OF IONIZATION AND DISSOCIATION OF MONOSILANE AND DISILANE

Appearance potentials of the principal positive ions from monosilane and disilane have been determined and upper limits to the heats of formation of the various ions have been derived, as well as a value of ΔHf°(SiH3) = 51 kcal/mol. From the energetic onsets of some of the resonance-capture processes and pair-production processes, thermochemical data for some of the negative ions from monosilane are derived. This is not possible in the case of disilane because it appears that all the negative ions are formed in different dissociation channels of common parent Si2H6-* ions and Si2H6* molecules.