Quantum mechanical study of the light-atom transfer reactions, O(3P)+XCl→OX+Cl (X=H,D). I. Reactions in the ground vibrational states

We present a three-dimensional quantum mechanical study of the light-atom transfer reaction O(3P)+XCl(vi=0)→OX(vf=0)+Cl(X=H,D), where vα represents the vibrational state in the α channel. The adiabatic-bend approximation reformulated in terms of the hyperspherical coordinates is employed to calculate the cross sections and rate constants. The potential energy surface used here is the Persky–Broida’s LEPS-I. The results are compared with the available experimental data and quasiclassical trajectory calculations. A discrepancy is found between the present results and the quasiclassical trajectory results at low collision energies (low temperatures). This is a clear manifestation of the quantum mechanical tunneling effect. The present results of the rate constants and the kinetic isotope effect are generally in better agreement with experiment. The previously proposed constant centrifugal potential approximation (CCPA) is directly demonstrated to work well.