Influence of chemical bonds on the lifetime of the molecular-field-split 2p levels in H2S

7 pages; International audience; Different lifetime broadenings in molecular-field-split 2p core levels in H2S are predicted theoretically and are identified in an experimental investigation of the S 2p Auger electron spectrum. The measurements were performed for the transition to the vibrationally resolved X1A1 ground state of H2S2+. The lifetimes of the 3e1/2 and 5e1/2 levels of the 2p ionized molecule are found to be 64 and 74 meV, respectively. This unambiguous determination of the lifetime difference of 10±1 meV is only possible as the 4e1/2→X1A1(2b1-2) decay channel that overlaps the 5e1/2→X1A1(2b1-2) channel is practically suppressed in Auger decay in H2S. The lifetime difference is confirmed by ab initio calculations. A theoretical analysis shows that it results from the mutual orientation of the core hole in the intermediate states and the valence electron density in the sulfur 3p orbitals. Both are strongly influenced by the chemical bond. Thus the observed effect is the direct result of a fundamental property of molecular electronic structure.