Abstract. 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 3 Σ + state of HeH + towards the 9 other 3 Σ + and 6 3 Π n = 2, 3 higher-lying electronic states are calculated, using the autocorrelation method introduced by Heller (1978) and the method based on the asymptotic behaviour of wavepackets introduced by Balint-Kurti et al. (1990). The corresponding radiative association cross sections are extracted from the same calculations, and the photodissociation and radiative association rate constants are determined.