Quantum mechanical study on energy dependence of probabilities of nonreactive vibrational transitions, atom exchange reaction, and dissociation in a collinear He+H-2(+) collision

The accurate time-independent quantum mechanical method developed by the pr esent authors [K. Sakimoto and K. Onda, J. Chem. Phys. 100, 1171 (1994)] is applied to investigate a nonreactive vibrational transition, atom exchange reaction, and dissociation processes in a collinear H-2(+)(v(i))+He collis ion. The algorithm based on the three-point finite difference formula is re placed with the Numerov algorithm to improve on numerical efficiency for di rectly solving the Schrodinger equation represented by the hyperspherical c oordinates (rho,omega). We have employed the interaction potential surface analytically fitted by Joseph and Sathyamurthy [J. Chem. Phys. 86, 704 (198 7)] for this collision system. The energy dependence of the probabilities o f the nonreactive vibrational transition, atom exchange reaction, and disso ciation processes is investigated at the total energy from 4 to 10 eV, and the dependence of these probabilities on the initial vibrational state of t he H-2(+)(v(i))(0 less than or equal to v(i)less than or equal to 17) ion i s also studied to understand deeply this collision dynamics. These probabil ities are undulatory as a function of the total energy, and show that the c oupling among the channels defined by the reactant and product vibrational bound and continuum states is strong. The atom exchange reaction is the dom inant process for v(i)less than or equal to 4, and the predominant process is dissociation of the H-2(+) for v(i)greater than or equal to 14 at the to tal energy investigated here. In order to clarify the sensitivity of this c ollision dynamics to the interaction potentials, we have investigated an ef fect of an additive two-body and nonadditive many-body interaction potentia ls on the nonreactive vibrational transition, atom exchange reaction, and d issociation processes. It is found that the collision dynamics is extremely sensitive to the short-range part of the potential energy surface. (C) 199 9 American Institute of Physics. [S0021-9606(99)01227-1].