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Guided ion beam mass spectrometry is used to measure cross sections as a function of kinetic energy for interaction of SiF,+ (x = 1-4) ions with Xe. Energy dependences of the collision-induced dissociation cross sections are analyzed to yield the following 0 K bond dissociation energies (BDEs): D(SiF3+-F) = 0.85 f 0.16 eV, D(SiF2+-F) = 6.29 f 0.10 eV, D(SiF+-F) = 3.18 f 0.04 eV, and D(Si+-F) = 7.04 f 0.06 eV. The ionization energies, IE(SiF2) = 10.84 f 0.13 eV and IE(SiF3) = 9.03 f 0.05 eV, are also measured from analysis of endothermic charge transfer reactions. From these BDEs and IEs, previous results of Weber and Armentrout [J. Chem. Phys. 1988,88,6898], and work in the preceding paper, we derive heats of formation for the silicon fluoride cations and neutrals that provide a self-consistent set of thermochemical data for the silicon fluoride species. In some cases, the thermochemical values determined here are considerably different from available literature values but are in good agreement with theory. The differences are discussed in detail.

Guided ion beam mass spectrometry is used to measure the cross sections for collision-induced dissociation of SFx+ (x=1–5) with Xe. The energy dependences of the cross sections are analyzed to give the following 0 K bond dissociation energies (BDEs): D°(SF4+–F)=4.60±0.10 eV, D°(SF3+–F)=0.36±0.05 eV, D°(SF2+–F)=4.54±0.08 eV, D°(SF+–F)=4.17±0.10 eV, and D°(S+–F)=3.56±0.05 eV. The ionization energies, IE(SF)=10.16±0.17 eV, IE(SF3)=8.18±0.07 eV, IE(SF4)=11.69±0.06 eV, and IE(SF5)=9.60±0.05 eV, are also measured from analysis of endothermic charge–transfer reactions. From these BDEs and IEs, we derive heats of formation for the sulfur fluoride ions and neutrals that provide a self-consistent set of thermochemical data for the sulfur fluoride species. In some cases, the thermochemical values determined here are considerably different from available literature values. These differences are discussed in detail.

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Guided ion beam techniques are used to measure cross sections as a function of kinetic energy for the reactions of silane with M+ = Sc+, Y+, La+, and Lu+. Ionic products include MH+ and MH2+, as well as MSiH,+ (x = 0-3). The major low-energy process in all four systems is formation of MSiH2+ + H2, while at higher energies, formation of MH+ + SiH3 and MH2' + SiH2 dominates the reactivity. Variation of source conditions allows the effect of electronic excitation on the reactivity of Sc+ and Y+ to be studied in detail. The Sc+ (a3D) ground state and the Y+ (a3D) f i s t excited state are approximately an order of magnitude less reactive than the Sc+ (a'D, a3F) excited and the Y+ (a%) ground states. Formation of ScH2+ + SiH2 is observed only for reaction of silane with Sc'