Excitation of a core electron to the lowest unoccupied orbital of H2S has been shown to give rise to dissociation that occurs faster than the Auger decay. Recent experimental data have allowed us to resolve vibrational structures connected with the resonant Auger decay in the core excited S*H fragment. At some photon energies, hot bands resulting from the decay of the vibrationally excited levels, v = 1 andv = 2, in the core excited fragment are observed. A new generalised potential energy surface for the 2p-16a1 state of H2S is presented. Calculations of the vibrationally excited states at different points through the dissociation channel of the potential energy surface are presented. These allow determination of the point on the surface which has vibrational splitting consistent with the experimental values, revealing the geometry of the fragment when the core excited state decays. A new method, based on the core hole lifetime as an internal "stop-watch", to determine the characteristic time for dissociation of the H2S* molecule into H and S* H fragments from experimental data is presented. This result is compared with values obtained using the potential energy surface calculations.
Fast dissociation of resonantly core excited H2S studied by vibrational and temporal analysis of the Auger spectra
1997
Abstract
Excitation of a core electron to the lowest unoccupied orbital of H2S has been shown to give rise to dissociation that occurs faster than the Auger decay. Recent experimental data have allowed us to resolve vibrational structures connected with the resonant Auger decay in the core excited S*H fragment. At some photon energies, hot bands resulting from the decay of the vibrationally excited levels, v = 1 andv = 2, in the core excited fragment are observed. A new generalised potential energy surface for the 2p-16a1 state of H2S is presented. Calculations of the vibrationally excited states at different points through the dissociation channel of the potential energy surface are presented. These allow determination of the point on the surface which has vibrational splitting consistent with the experimental values, revealing the geometry of the fragment when the core excited state decays. A new method, based on the core hole lifetime as an internal "stop-watch", to determine the characteristic time for dissociation of the H2S* molecule into H and S* H fragments from experimental data is presented. This result is compared with values obtained using the potential energy surface calculations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
