• Medientyp: E-Artikel
  • Titel: Observation of relativistic E⊗e vibronic coupling in Rb3 and K3 quartet states on helium droplets
  • Beteiligte: Auböck, G.; Nagl, J.; Callegari, C.; Ernst, W. E.
  • Erschienen: AIP Publishing, 2008
  • Erschienen in: The Journal of Chemical Physics, 129 (2008) 11
  • Sprache: Englisch
  • DOI: 10.1063/1.2976765
  • ISSN: 0021-9606; 1089-7690
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  • Beschreibung: Spectroscopy of alkali-metal complexes on helium droplets (HeN, N=1000–10000) provides the unique opportunity to observe high-spin species, which exhibit prominent spin-orbit (SO) effects. In this work we present laser-induced-fluorescence and magnetic-circular-dichroism (MCD) spectra of the (2)E′4←(1)A2′4 band of Rb3 and K3 on HeN. For Rb3 we find a progression of four SO split bands, weakly perturbed by linear vibronic [Jahn–Teller (JT)] coupling. The K3 transition was previously observed and interpreted in terms of linear and quadratic JT effects in the (2)E′4 state [J. H. Reho et al., J. Chem. Phys. 115, 10265 (2001)]. The structure of the MCD spectrum, however, clearly reveals the importance of SO coupling also for the K3 transition and suggests a different assignment with weak linear JT and nonsignificant quadratic JT coupling. The observed strong C-type MCD spectra arise from different populations of the ground-state Zeeman sublevels. Thus a quantitative analysis allows a determination of the spin temperature, and since alkali-metal complexes are situated on the surface of the helium droplet this corresponds to a determination of the surface temperature. Our results from the trimer spectra are consistent with the value of ≈0.4K, which is found in the interior of a droplet and which we already confirmed for the surface from the spectra of triplet-state alkali-metal dimers in a previous work.