Competition between direct dissociation and resonant Auger decay: a quasi-classical model applied to the 2p−1 σ∗ states of HCl, DCl and Cl2

Resonant Auger spectra of HCl, DCl, and Cl2 following the (Cl 2p32 → σ∗ excitation were studied. Both ‘molecular’ and ‘atomic’ Auger transitions are observed and assigned. The branching ratio of ‘molecular’ versus ‘atomic’ Auger transitions increases with increasing reduced mass of the target molecules. Using a quasi-classical model, we are able to deduce the principal Auger lineshape in agreement with experiment. The simultaneous occurrence of ‘atomic’ and ‘molecular’ Auger transitions is shown to be the general case for repulsive intermediate states. The kinematic model successfully describes the mass and lifetime dependence of the competition between the Auger process and dissociation.