Rates of reaction of hydrogen atoms with silane and germane

Abstract

The rates of reaction of hydrogen atoms with silane, germane, and (for comparison) ethylene have been determined at 20 Torr in a discharge flow system. The apparent bimolecular rate constants are 8.5 X 10~12, 4.3 X 10"10, and 3.5 X 10"13 cm3 molecule"1 sec"1, respectively, which are substantially larger than previously reported values. Activation energies were calculated by the empirical methods of Johnston (BEBO) and Spirin and compared with the values estimated from the experimental rate constants. The experimentally estimated values are lower than those predicted by the BEBO method, suggesting that the activated complex for reaction of hydrogen atoms with silane and germane may differ from the simple linear model for hydrogen atom transfer. * To whom correspondence should be addressed at Washington University.netic study of reactions of atomic hydrogen with the methane analogs silane and germane has been published until recently.3Recently reactions of hydrogen atoms,4 methyl radical,5 and trifluoromethyl radical6 with silicon and germanium hydrides and alkylsilanes have been reported. The results

Kinetic isotope effect for the reaction of H atoms with GeH4 and GeD4

“…From the figure it can be seen that our results are in good agreement with our previous work [3], and with the values obtained by Stief and co-workers [10]. Not shown are the rate constants reported by Choo et al [11] and Austin and Lampe [12], which differ markedly from the more recent data.…”

Quasiclassical trajectory study of the SiH4+H→SiH3+H2 reaction on a global ab initio potential energy surface

“…The rate coefficients have been measured with a wide variety of experimental methods, [5][6][7][8][9][10][11][12][13][14][15][16] but most work has been carried out at room temperature and only a few recent studies 10,11,16 reported the temperature dependence of the rate coefficient. For example, Arthur [10][11][12][13][14][15][16] However, a detailed state-resolved dynamical experimental investigation is still lacking for the title reaction.…”

Gas‐Phase Chemistry and Mass Spectrometry ofGe‐,Sn‐ andPb‐Containing Compounds

“…Recent measurements 216,217 for this reaction in the range of T = 293-473 K have settled the question of the rate constant that was in serious doubt from the early experiments 218,219 . Reaction 43 is characterized by a very low activation energy of 7.3 ± 0.2 kJ mol −1 , and an isotope effect k H /k D = 2.0 ± 0.4 at 300 K obtained by comparison with the reaction of H atom with fully deuteriated monogermane 220 .…”