GUIDED ION-BEAM STUDIES OF THE REACTION OF SI+ (P-2) WITH METHYLSILANE - REACTION-MECHANISMS AND THERMOCHEMISTRY OF ORGANOSILICON SPECIES

Reaction of ground-state Si+ (2P) with methylsilane (SiH3CH3) is studied from thermal to 10-eV kinetic energy by using guided ion beam mass spectrometry. The major products at thermal energies are SiCH3+, Si2HCH3+, and, above 1 eV, SiH2CH3+. Labeling experiments involving Si-30+ provide additional mechanistic information that SiCH3+ is formed via three different mechanisms. The general mechanistic details of this system can be understood by extending the potential energy surfaces previously calculated by Raghavachari (J. Phys. Chem. 1988, 92, 6284). New thermodynamic information regarding the disilicon ions Si2H2CH3+, Si2HCH3+, Si2CH3+, and Si2CH2+, as well as the SiCH3, SiH2CH3, and SiH2(CH3)2 neutrals and the SiHCH3+ and SiH2CH3+ ions, are provided and discussed. Comparisons to prior experimental results and theoretical predictions are made.