Ab initio molecular dynamics around a conical intersection: Li(2p)+H-2

We present ab initio multi-electronic state molecular dynamics for a polyatomic complex accessing a conical intersection. The potential energy 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 quenching efficiency is greatly diminished by recrossing from the lower to the upper adiabatic electronic state. We observe electronic quenching followed by both inelastic and reactive scattering, a testament to the flexibility of the ab initio potential energy surfaces and our allowance for wavepacket bifurcation in multiple spawning dynamics. (C) 1997 Elsevier Science B.V.