Photodissociation of HeH²⁺and flux deficiency of stellar spectra

Accurate quantal values of photodissociation cross sections have been calculated for HeH 2+ for the transition 2p sigma to 3d sigma over the accessible range of lambda lambda 800-5800 AA and an attempt has been made to explain whether this is the source of the well known ultraviolet flux deficiency observed by Stecher and Milligan (1962) in a number of early type stars. The cross sections were calculated for all the vibrational levels of the 2p sigma state for which the Boltzmann distribution has been assumed and for the two most probable rotational-level values at stellar temperatures of 20000K and 28000K. It has been concluded that HeH 2+ cannot be the source of such stellar opacity.