Rovibrationally resolved photodissociation of HeH+

Abstract

Accurate photodissociation cross sections have been obtained for the A 1Σ+ ← X1Σ+ electronic transition of HeH+ using ab initio potential curves and dipole transition moments. Partial cross sections have been evaluated for all rotational transitions from the vibrational levels v″ = 0-11 and over the entire accessible wavelength range λλ100-1129. Assuming a Boltzmann distribution of the rovibrational levels of the X1Σ + state, photodissociation cross sections are presented for temperatures between 500 and 12,000K. A similar set of calculations was performed for the pure rovibrational photodissociation in the X 1Σ+ electronic ground state, but covering photon wavelengths into the far-infrared. Applications of the cross sections to the destruction of HeH+ in the early universe and in UV-irradiated environments such as primordial halos and protoplanetary disks are briefly discussed. © 2011. The American Astronomical Society. All rights reserved..