Dissociation of excited diatomic molecules by external perturbations

1.Introduction .—An excited attractive state of a diatomic molecule, in the absence of an external field, is not affected by the crossing of a repulsive state with different symmetry. An appropriate external field will, however, induce perturbations between the two states. It is generally recognized that the probability of transition from an attractive to a repulsive state, during one oscillation, will be very small, except when the molecule is in an energy level, E, which is very close to the value of the potential energy at the point of crossing, V0 . However, even a very small transition probability, per oscillation, may give a high probability that the molecule will dissociate before returning, by radiation, to the normal state. Hence the calculation of these small probabilities is of interest.