Photodissociation of HeH+by both electronic and vibrational transitions

The partial cross sections for photodissociation of HeH + by both electronic (X 1 Sigma + to A 1 Sigma + ) and vibrational (X 1 Sigma + to X 1 Sigma + ) excitations have been studied by the first-order perturbation method. These cross sections sigma vj have been calculated for each of the vibrational levels from v=0 to 8 and for the rotational level j=1 of the ground electronic state. The maximum order of the photodissociation cross section by electronic excitation is 10 -1 AA 2 which is similar to that observed for H 2 + (and its isotopes). For photodissociation by vibrational excitation, the cross sections are of the order of 10 -3 AA 2 for the v=8 and 7 levels and decrease gradually to 10 -1 AA 2 for v=0. The special features of the photodissociation cross sections due to the heteropolarity of HeH + are discussed in detail by comparison with the results obtained for H 2 + and HD + .