AB-INITIO MOLECULAR-DYNAMICS AROUND A CONICAL INTERSECTION - LI(2P)-2(H)

We present ab initio multi-electronic state molecular dynamics for a p olyatomic complex accessing a conical intersection. The potential ener gy surfaces and their couplings are generated simultaneously with the solution of the nuclear Schrodinger equation. For the chosen example, nonadiabatic transitions are extraordinarily fast (< 10 fs) and the qu enching efficiency is greatly diminished by recrossing from the lower to the upper adiabatic electronic state. We observe electronic quenchi ng followed by both inelastic and reactive scattering, a testament to the flexibility of the ab initio potential energy surfaces and our all owance for wavepacket bifurcation in multiple spawning dynamics. (C) 1 997 Elsevier Science B.V.