A two-photon resonance enhanced multiphoton ionization spectroscopic study on the mercapto radical is carried out in the one-photon energy region between 258 and 208 nm. Thirteen previously unobserved Rydberg states converging upon the a 1Δ or b 1Σ+ excited ionic states are reported. Identification and characterization of several states with excitation energies below the lowest ionization limit are performed by analyses of the rotationally resolved two-photon excitation spectra, polarization studies, and photoelectron spectroscopy after excitation of the states. Detailed comparisons between the experimental and simulated excitation spectra, which show for three states clear indications of intensity anomalies, as well as the observation of multiple ionization channels demonstrate that for all states Rydberg–Rydberg and/or Rydberg–valence interactions determine the finer details of their electronic wave functions. Above the lowest ionization limit two-photon resonance enhancement is observed for six Rydberg states. These states are found to ionize by autoionization, rather than by absorption of a third photon. Remarkably, rotationally well-resolved excitation spectra can still be obtained for two of these states. Comparison of the dominant electronic configuration of the six Rydberg states allows us to explain these differences in terms of the possible autoionization channels.

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Zero-kinetic-energy pulsed-field ionization spectroscopy of the a 1D state of SH+ (SD+).Milan, J.B.; Buma, W.J.; de Lange, C.A. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. The results of a zero-kinetic-energy pulsed-field ionization study on the a 1 ⌬ (v ϩ ϭ0) excited ionic state of SH ϩ ͑SD ϩ ͒ obtained via two-photon excitation of the [a 1 ⌬]3d 2 ⌽ (vЈϭ0) Rydberg state and subsequent one-photon pulsed-field ionization are reported. Accurate ionization energies as well as rotational constants are obtained. A detailed comparison between the rotational branching ratios resulting from the pulsed-field ionization process and those of a direct ionization process is made. The results elucidate the dynamics of the high-n Rydberg states involved in pulsed-field ionization of SH ͑SD͒.

Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. energy which exceeds the lowest ionization energy, ionization is observed to occur preferentially by the absorption of a third photon after the two-photon excitation step, rather than through autoionization. Photoelectron spectra show a large asymmetry in the rotational branching ratios, which is attributed to the high value of A + in the ionic state.

Several previously unobserved Rydberg states of the sulphur atom above the lowest ionization threshold are identified and assigned using (2ϩ1) resonance-enhanced multiphoton-ionization photoelectron spectroscopy. All states were accessed by two-photon transitions from either the 3 P ground or the 1 D excited state, prepared by in situ photodissociation of H 2 S. The observed states derive from the ( 2 D o )5p and ( 2 P o )4p configurations. For the ( 2 D o )5p 3 F and ( 2 P o )4p 3 D triplets, extensive photoelectron spectroscopic studies enable a detailed comparison of the autoionization and photoionization rates of these states.