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Title:2OH overtone spectroscopy of water-containing van der waals species
Author(s):Vanfleteren, Thomas
Contributor(s):Coudert, L. H.; Loreau, Jérome; Liévin, Jacques; Herman, Michel; Földes, Tomas
Abstract:We have used continuous-wave cavity ring-down spectroscopy to record part of the 2OH excitation range in an Ar/Kr supersonic expansion seeded with H$_2$O. Various bands were observed, and are being rotationally analyzed, of Ar$-$H$_2$O and Kr$-$H$_2$O. The analysis of experimental linewidths allowed us to determine the mean upper state predissociation lifetime to be 3~ns for Ar$-$H$_2$O and 4~ns for Kr$-$H$_2$O. In this talk, the latest results concerning Ar$-$H$_2$O will be presented. Several bands were identified and analyzed, highlighting some strong perturbations. The assignment of the many bands, as well as the perturbation processes, is complicated and is still in progress. The results of the analysis will be presented along with the perturbing effects of the dark states. Identification of these will be attempted using a multidimensional approach, based on the intramolecular potential energy surface of water monomer\footnote{H.\ Partridge and D.\ W.\ Schwenke, {\em J.\ Chem.\ Phys.}~{\bf 106} (1997) 4618.} and on the intermolecular potential energy surface of the complex, allowing us to evaluate the rovibrational energy levels of H$_2$O perturbed by the argon atom. Although several such intermolecular potentials are already available, like those reported by Makarewicz\footnote{J.\ Makarewicz, {\em J.\ Chem.\ Phys.}~{\bf 129} (2008) 184310.} and by Hou {\em et al.,}\footnote{D.\ Hou, Y.-T.\ Ma, X.-L.\ Zhang, and H.\ Li, {\em J.\ Chem.\ Phys.}~{\bf 144} (2016) 014301.} none of them can be used in the present investigation as they were designed for vibrational states of the water monomer below the (101) state, involved in the present spectra. A 6D intermolecular potential energy surface is currently being computed through {\em ab initio} calculations to deal with high lying states of the water monomer like the (101) state. With the help of this new surface and of the multidimensional approach, we are hoping to assign the bright and the dark states of the complex, near 7\,500~cm$^{-1}$, involved in the present spectra.
Issue Date:2016-06-23
Publisher:International Symposium on Molecular Spectroscopy
Genre:Conference Paper/Presentation
Rights Information:Copyright 2016 by the authors
Date Available in IDEALS:2017-01-26

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