Taylor & Francis Group
tmph_a_2281592_sm8000.dat (35.88 kB)

Measurements of H2O-O2 line shape parameters and the determination of the intermolecular potential for modified complex Robert-Bonamy calculations

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posted on 2023-11-20, 18:21 authored by Robert R. Gamache, Nicholas Orphanos, Bastien Vispoel, Keeyoon Sung, Geoffrey C. Toon

A series of spectra, one pure H2O and four H2O-O2 mixtures, were measured for the ν2 band in the 1200–1950 cm−1 region at room temperature using a single-pass copper cell housed in the Bruker 125HR high-resolution Fourier transform spectrometer (FTS) at Jet Propulsion Laboratory (JPL). All the five spectra were fit simultaneously using a multispectrum non-linear least-squares fitting software, Labfit programme suite, which adopts a speed-dependent Voigt line shape profile using full line mixing taken into account through a relaxation matrix operation. O2-broadened half-width and O2-induced frequency shift coefficients were determined for more than 350 transitions of H216O. These data were then checked using the smooth variation and paring rules [Brown et al. J Mol Spectrosc. 2007;246:1-21, Ma et al. Mol Phys. 2011;109:1925-41] and 186 transitions that obey the rules with less than 3% difference were chosen. Using these selected data, Modified Complex Robert-Bonamy calculations were made to determine the intermolecular potential for the H2O-O2 collision system. Some 93 potential were investigated resulting in a final potential (potential 74) that agrees with the selected half-width measurements having an average percent difference of 0.052 and a standard deviation of 5.108% between measurement and calculations.


The research at the Jet Propulsion Laboratory (JPL), California Institute of Technology, was performed under contracts with the National Aeronautics and Space Administration. R.R. Gamache, K. Sung, and G. Toon are pleased to acknowledge support from NASA ROSES-NRA: NNH20ZDA001N-XRP [grant number 20-XRP20_2-0063]. B. Vispoel would like to thank the F.R.S.-FNRS for postdoctoral financial support.