A theoretical study on an isotope effect in the CH 3+H 2 → CH 4+H reaction

Abstract

Vibrationally adiabatic ground-state potential curves for the CH 3+H 2 → CH 4+H (I) and CD 3+H 2 → CD 3H+H (II) reactions were obtained by adding zero-point energies of harmonic vibrations orthogonal to intrinsic reaction coordinate (IRC) to the bare potential curves along IRC. It was clarified that both the barrier height and barrier width of reaction II are smaller than those of reaction I. This computational result qualitatively explains the experimental observation of T. Momose, H. Hoshina, N. Sogoshi, H. Katsuki, T. Wakabayashi, T. Shida [J. Chem. Phys. 108 (1998) 7334] that reaction II occurs but reaction I does not occur in solid parahydrogen at 5 K.