A STUDY OF CONICAL INTERSECTION EFFECTS ON SCATTERING PROCESSES - THEVALIDITY OF ADIABATIC SINGLE-SURFACE APPROXIMATIONS WITHIN A QUASI-JAHN-TELLER MODEL

Conical intersections between Born-Oppenheimer potential energy surfac es create singularities which are known to have a direct effect on the symmetry of the nuclear wave functions. In this article is presented a quasi-Jahn-Teller model to study the symmetry effects of these singu larities on nonreactive and reactive scattering processes. Applying th is model, we were able to determine in what way and to what extent the conical intersection affects the relevant S-matrix elements. Having t he results of this study available, conclusions concerning more realis tic systems were derived. (C) 1996 American Institute of Physics.