Thermochemistry of the SiH3+(SiH4)n and SiH3+(H2)n cluster ions

Gas-phase clustering reactions of SiH3+ with SiH4 and H2 were studied using a pulsed-electron beam mass spectrometer. The bond dissociation energy of SiH3+ … SiH4 was estimated to be ⩾35 kcal/mol and those of SiH3+ (H2)n with n = 1 and 2 were measured to be 14.2 and 4.8 kcal/mol in good agreement with the theoretical values. The clusters are found to have the shell structures, SiH3+ (sol)2(sol)n−2 for both sol = SiH4 and H2.