Infrared Spectra of the Water-CO2 Complex in the 4.3-3.6 μm Region and Determination of the Ground State Tunneling Splitting for HDO-CO2.

Spectra of water─CO2 dimers are studied using a tunable mid-infrared source to probe a pulsed slit jet supersonic expansion. H2O-CO2 and D2O-CO2 are observed in the CO2 ν3 fundamental region (≈2350 cm-1), D2O-CO2 is also observed in the D2O ν3 fundamental region (≈2790 cm-1), and HDO-CO2 is observed in the HDO O-D stretch fundamental region (≈2720 cm-1), all for the first time in these regions. Analysis of the spectra yields excited state rotational parameters and vibrational shifts. They also yield the first experimental values of the ground state internal rotation tunneling splittings for D2O-CO2 (0.003 cm-1) and HDO-CO2 (0.0234 cm-1). The latter value is a direct determination made possible by the reduced symmetry of HDO-CO2. These results provide stringent and easily interpreted tests for theoretical water-CO2 potential energy surface calculations.

[1]  P. Felker,et al.  Intermolecular rovibrational states of the H2O-CO2 and D2O-CO2 van der Waals complexes. , 2022, Journal of Chemical Physics.

[2]  A. S. Bogomolov,et al.  The rotationally resolved symmetric 2OH excitation in H2O-CO2 observed using pulsed supersonic expansion and CW-CRDS , 2021, Chemical Physics Letters.

[3]  M. Herman,et al.  High-resolution spectroscopic study of the H2O–CO2 van der Waals complex in the 2OH overtone range , 2020 .

[4]  A. Barclay,et al.  Spectra of the D2O dimer in the O-D fundamental stretch region: Vibrational dependence of tunneling splittings and lifetimes. , 2019, The Journal of chemical physics.

[5]  J. Bowman,et al.  Two-component, ab initio potential energy surface for CO2-H2O, extension to the hydrate clathrate, CO2@(H2O)20, and VSCF/VCI vibrational analyses of both. , 2017, The Journal of chemical physics.

[6]  N. Moazzen-Ahmadi,et al.  Spectroscopy of dimers, trimers and larger clusters of linear molecules , 2013 .

[7]  Y. Zhu,et al.  Infrared diode laser spectroscopy of H2O–CO2 and D2O–CO2 complexes in the v2 bend region of water , 2013 .

[8]  A. Harvey,et al.  Intermolecular potential energy surface and second virial coefficients for the water-CO2 dimer. , 2011, Journal of Chemical Physics.

[9]  J. Makarewicz.  Intermolecular potential energy surface of the water-carbon dioxide complex. , 2010, The Journal of chemical physics.

[10]  J. Makarewicz,et al.  Internal rotation effects and hyperfine structure in the rotational spectrum of a water–carbon dioxide complex , 1998 .

[11]  L. Pedersen,et al.  Wide amplitude motion in the water–carbon dioxide and water–acetylene complexes , 1992 .

[12]  K. I. Peterson,et al.  Structure and internal rotation of H2O–CO2, HDO–CO2, and D2O–CO2 van der Waals complexes , 1984 .