Landau-Zener transitions through small electronic eigenvalue gaps in the Born-Oppenheimer approximation
Résumé
We study the propagation of molecular wave packetsthrough the simplest two types of avoided crossings of electronic energy levels in a limit where the gap between the eigenvalues shrinks as the nuclear masses are increased. For these types of avoided crossings, the electron energy levels essentially
depend on only one of the nuclear configuration parameters, as is the case for all diatomic molecules. We find that the transition probabilities are of order 1 and are determined by the Landau-Zener formula.