Electronic density-matrix algorithm for nonadiabatic couplings in molecular dynamics simulations

Closed expressions for nonadiabatic couplings are derived using the collective electronic oscillators (CEO) algorithm based on the time-dependent Hartree-Fock equations. Analytic derivatives allow the calculation of transition density matrices and potential surfaces at arbitrary nuclear geometries using a molecular dynamics trajectory that only requires a CEO calculation at a single configuration. (C) 2001 John Wiley & Sons, Inc.