INTERFERENCE EFFECTS IN MOLECULAR-SYSTEM WITH CURVE CROSSING

The time-dependent behavior of molecular systems exhibiting a curve-cr ossing (either natural or photon-induced) is shown to exhibit marked i nterference patterns. These are particularly evident for single-mode h armonic systems and for weak inter-electronic coupling. It is shown th at, in the case of degenerate potential energy surfaces, interference gives rise to jumps in the transition probability (at each passage of the wavepacket through the crossing region) whose height depends on ti me. In the case of non-degenerate potential energy curves, depending o n the energy gap, one may observe a periodic or quasi-periodic behavio r. Including additional modes results in a decrease of interferential features. (C) 1998 Elsevier Science B.V. All rights reserved.