Theoretical work on the water monomer Matt Barber Jonathan Tennyson University College London
Outline of work so far Improvements to water line list Extended to cover 13,071-17,600 cm -1 Corrected to add some missing lines Extend to infra-red? Water monomer band intensities To approximate water dimer spectrum Can be built from monomer dipole surface Partition function for water dimer Few energy levels filled at low temperatures
Line lists HITRAN Good reference for strong lines BT2 R J Barber and Jonathan Tennyson, UCL Theoretical model with experimentally determined energy levels. Retrofitted experimental spectra Tolchenov R, Tennyson J: "Water line parameters from refitted spectra constrained by empirical upper state levels: study of the cm-1 region". JQSRT, 109(4), (2008). Grenoble data Very accurate measurements using cavity ring down spectroscopy Comparatively clean area for HITRAN lines
H 2 O monomer band intensities Fits into Franck-Condon approximation Only considering vibrational transitions Only one excited monomer Two leads to dissociation CVR potential surface Lodi L, Tolchenov R, Tennyson J, Lynas-Gray AE, Shirin SV, Zobov N, Polyansky OL, Csaszar AG, van Stralen JNP, Visscher L.: "A new ab initio ground state dipole moment surface for the water molecule". J. Chem. Phys., in press. Valence-only (V) dipole with core (C) and relativistic (R) corrections Test for consistency against publications HITRAN 1994 Jorgensen & Jensen (1993)
Dimer partition function at 20K Only lowest vibrational state occupied Statistical weights from Groenemboom et al. G 16 Symmetry Need rotational energy levels Ross is working on this Equation:
Conclusion Monomer linelist Extend to infra-red? Monomer band intensities In progress Dimer partition function 20K soon 300K eventually Anything else in between?