Shen-Min Li

Direct dynamics study of the reaction path and rate constants of NH2+C2H6 → NH3+C2H5

Abstract The title reaction is studied by ab initio molecular orbital theory. The geometries for the reactants, products and transition state are optimized at the UMP2/6-311+G ∗∗ level, and then the minimum energy path is built up by means of the intrinsic reaction coordinate method. In order to improve the energetics along the minimum energy path, single-point calculation is carried out by using Gaussian-2 theory. Furthermore, the forward and reverse rate constants for the temperature range from 300 to 2100 K are obtained by the canonical variational transition state theory with small-curvature tunneling correction method. It is shown that the calculated rate constants are in good agreement with the experimental values.

Direct ab initio dynamics study on the reaction paths and rate constants of hydrogen atoms with methylgermanes GeH3CH3 and GeH2(CH3)2

Abstract Direct ab initio dynamical calculations at the PMP4SDTQ/6-311+G(3df,2p)//MP2/6-31+G(d) level have been performed on the reactions of atomic hydrogen with methylgermanes, GeH3CH3 and GeH2(CH3)2, over the temperature range 200–2000 K. The obtained CVT/SCT thermal rate constants are in good agreement with available experimental values. The results show that the variational effect and small-curvature tunneling effects are unimportant for the two reactions over the whole temperature range. The rate constants are fitted to the three-parameter expressions over the whole temperature range 200–2000 K: k( GeH 3 CH 3 + H )=1.815×10 8 T 1.817 exp (−691/T) cm 3 mol −1 s −1 and k[ GeH 2 ( CH 3 ) 2 + H ]=2.448×10 8 T 1.727 exp (−639/T) cm 3 mol −1 s −1 .