Photodissociation of HgBr, XΣ1/2

Abstract
Transition moments and energies have been calculated for the X‐A, bound to continuum, transition in HgBr. Absorption at the laser wavelength of 502 nm has been examined for two sets of absorbing states: A thermal distribution of vibrational levels at 500° K and the terminus vibrational level of the B‐X laser transition. In the first case a cross section of 7×10−20 cm2 is calculated. Since no fast reaction for removal of the X state is known, the number density can exceed 1016 cm−3 and a significant absorption will result in late times. In the second case the laser photon can be coherently absorbed in the X‐A transition leading to photon induced predissociation of the v = 0, B state. An upper bound to the predissociation rate for a 2‐MW/cm2s flux is 106 s−1. Electron dissociative attachment of the X state is also shown to be improbable as a means of fast removal. Energy curves of the ground states of both the neutral and negative ion of HgBr are shown not to cross in any accessible region.