OBSERVATION OF THE 5 $^{1}\Sigma_u^+$ and 5 $^{1}\Pi_u$ STATES OF Rb$_2$ BY POLARISATION LABELLING SPECTROSCOPY
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Date
2013
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Publisher
Ohio State University
Abstract
Two-colour polarization labeling experiments have been used to explore the excitation spectrum of the rubidium dimer in the region 25500 - 27000 cm$^{-1}$, aiming to establish the symmetry of excited states observed by Han and Heaven {J. Han, M. Heaven, J. Mol. Sprectrosc. 268, 37-41 (2011)} in earlier work. The spectra we recorded in fact probe quite different electronic states; we identify them from $ab\ initio$ calculations as the 5~$^{1}\Sigma_u^+$ and 5~$^{1}\Pi_u$ states, dissociating to Rb 5s + Rb 5d atoms. The home-made pulsed laser used to label levels in the electronic ground state, with nominal linewidth of 0.3 cm$^{-1}$, is not sufficiently selective for this heavy-alkali species. The spectra are a tangled confusion of short and rather irregular progressions of P,R doublets and/or Q lines. We have had to use cross-correlation techniques to identify transitions seen in different spectra that share a common ground state level, to establish assignments. Analysis confirms unusual vibrational patterns in the lowest vibrational levels, from avoided crossings with ion pair states.
Description
Supported by the PAN-CNRS exchange programme, 2011-12.
Author Institution: Institute of Physics, Polish Academy of Sciences, Al.; Lotnikov 32/46, 02-668 Warsaw, Poland\; Institute of Experimental Physics, Department of Physics, University of Warsaw, ul.; Hoza 69, 00-681 Warsaw, Poland\; Institut Lumiere Matiere, Universite Lyon 1 \& CNRS UMR5306, Universite de Lyon, France
Author Institution: Institute of Physics, Polish Academy of Sciences, Al.; Lotnikov 32/46, 02-668 Warsaw, Poland\; Institute of Experimental Physics, Department of Physics, University of Warsaw, ul.; Hoza 69, 00-681 Warsaw, Poland\; Institut Lumiere Matiere, Universite Lyon 1 \& CNRS UMR5306, Universite de Lyon, France