Determination of photodissociation and radiative association cross sections from the same time-dependent calculation

We illustrate some of the difficulties that may be encountered when computing photodissociation and radiative association cross sections from the same time-dependent approach based on wavepacket propagation. The total and partial photodissociation cross sections from the thirty-three vibrational levels of the b triplet {\Sigma}+ state of HeH+ towards the 9 other triplet {\Sigma}+ and 6 triplet {\Pi} n = 2, 3 higher-lying electronic states are calculated. The corresponding radiative association cross sections are extracted from the same calculations, and the photodissociation and radiative association rate constants are determined.