FAST DISSOCIATION OF RESONANTLY CORE-EXCITED H2S STUDIED BY VIBRATIONAL AND TEMPORAL ANALYSIS OF THE AUGER-SPECTRA

Excitation of a core electron to the lowest unoccupied orbital of H2S has been shown to give rise to dissociation that occurs faster than th e Auger decay. Recent experimental data have allowed us to resolve vib rational structures connected with the resonant Auger decay in the cor e excited SH fragment. At some photon energies, hot bands resulting f rom the decay of the vibrationally excited levels, v = 1 and v = 2, in the core excited fragment are observed. A new generalised potential e nergy surface for the 2p(-1)6a(1) state of H2S is presented. Calculati ons of the vibrationally excited states at different points through th e dissociation channel of the potential energy surface are presented. These allow determination of the point on the surface which has vibrat ional splitting consistent with the experimental values, revealing the geometry of the fragment when the core excited state decays. A new me thod, based on the core hole lifetime as an internal ''stop-watch'', t o determine the characteristic time for dissociation of the H2S molec ule into H and SH fragments from experimental data is presented. This result is compared with values obtained using the potential energy su rface calculations. (C) 1997 Elsevier Science B.V.