Dynamics of (H-,H2) collisions: A time-dependent quantum mechanical investigation on a new ab initio potential energy surface.

A global analytical potential energy surface for the ground state of H3- has been constructed by fitting an analytic function to the ab initio potential energy values computed using coupled cluster singles and doubles with perturbative triples [CCSD(T)] method and Dunning’s augmented correlation consistent polarized valence triple zeta basis set. Using this potential energy surface, time-dependent quantum mechanical wave packet calculations were carried out to calculate the reaction probabilities (PR) for the exchange reaction H-+H2(v,j)→H2+H-, for different initial vibrational (v) and rotational (j) states of H2, for total angular momentum equal to zero. With increase in v, the number of oscillations in the PR(E) plot increases and the oscillations become more pronounced. While PR increases with increase in rotational excitation from j=0 to 1, it decreases with further increase in j to 2 over a wide range of energies. In addition, rotational excitation quenches the oscillations in PR(E) plots. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]