Characterization of the excited electronic states of the SH radical by ab initio methods
Titel:
Characterization of the excited electronic states of the SH radical by ab initio methods
Auteur:
Bruna, Pablo J. Hirsch, Gerhard
Verschenen in:
Molecular physics
Paginering:
Jaargang 61 (1987) nr. 6 pagina's 1359-1380
Jaar:
1987-08-20
Inhoud:
Ab initio MRD-CI calculations have been performed for the SH radical in its low-lying valence states as well as vertically for the first Rydberg terms (2π24s, 2π24p and 2π23d). The lowest 1 4,2Σ-, 1 2Δ and 2 2Σ+ states are found to be of valence character in the vertical region, while a Rydberg structure was suggested by an earlier ab initio study. For the bound X 2Πi and A 2Σ+ various molecular constants such as spectroscopic parameters, dipole moments, Franck-Condon factors and spin-orbit constant are reported. The predissociation of A2Σ+ in its low-vibrational levels observed by Ramsay is confirmed to be caused by the repulsive 1 4,2Σ- states. Furthermore, a complete reassignment of the electronic structure of the experimentally measured Rydberg levels is given: all these states are found to have a 2π24s (B 2Σ- and C 2Δ), 2π23dσ (E2Σ-) and 2π2ndσ, n = 3-6 (D, F, G, H 2Δ) electronic configuration respectively. The E2Σ- and C2Δ states are classified here for the first time, while the B2Σ- has been reclassified with respect to prior theoretical work. An earlier experimental assignment of the higher 2Δ levels given by Morrow, namely 2π2ns (n = 5-8), is found to be in contradiction with an applied ionization limit correlating with SH+ in its X 3Σ- state.
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