Cross sections for the radiative association of He(1s3s 3S) + H+ (black curves), He(1s3p 3Po) + H+ (red curves) and He(1s3d 3S) + H+ (blue curves) towards the b 3Σ+ state of HeH+ with (full lines) and without (dashed lines) taking the vibrational dependence of the cross sections into account

Figure 7. Cross sections for the radiative association of He(1s3s 3S) + H+ (black curves), He(1s3p 3Po) + H+ (red curves) and He(1s3d 3S) + H+ (blue curves) towards the b 3Σ+ state of HeH+ with (full lines) and without (dashed lines) taking the vibrational dependence of the cross sections into account.

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 33 vibrational levels of the b 3Σ+ state of HeH+ towards the nine other 3Σ+ and 6 3Π n = 2, 3 higher lying electronic states are calculated, using the autocorrelation method introduced by Heller (1978 J. Chem. Phys. 68 3891) and the method based on the asymptotic behaviour of wavepackets introduced by Balint-Kurti et al (1990 J. Chem. Soc. Faraday Trans. 86 1741). The corresponding radiative association cross sections are extracted from the same calculations, and the photodissociation and radiative association rate constants are determined.