6.2 μm spectrum and 6-dimensional morphed potentials of OC-H2O

Abstract

Rovibrational transitions associated with tunneling states in the n 5 (water bending) vibration of the OC-H 2 O complex have been recorded using a supersonic jet mode-hop free quantum cascade laser spectrometer at 6.2 µm. Analysis of the resulting spectra is facilitated by incorporating fits of previously recorded microwave and submillimeter data accounting for Coriolis coupling to confirm assignment of the n 5 vibration. The theoretical basis of morphing a 5-D frozen monomers potential was initially developed and then extended to two 6-D morphed potentials. A combination of these spectroscopic results and previous rovibrational data for the n 5 vibration in OC-D 2 O are then used to generate a 6-D morphed potential surface for the intermolecular and the water bending vibrations. An alternative 6-D morphed potential of the intermolecular and the

The water–carbon monoxide dimer: new infrared spectra, ab initio rovibrational energy level calculations, and an interesting in-termolecular mode

“…Rivera-Rivera et al 6 have calculated intermolecular vibrational frequencies for H2O-CO (their Table 13) which can be compared with our Table 1. Their first mode at 19.73 (A state) and 18.64 cm -1 (B state) was labeled by them as 9 "in-plane bend", but it clearly must be the ground state K = 1 level, which we calculate at 19.868/18.871 cm -1 (relative to the respective K = 0 levels).…”

“…There has been considerable progress in observing mid-infrared rotation-vibration spectra. Thus Brookes and McKellar 1 studied the C-O stretch region (4.7 µm), Oudjeans and Miller 4 the O-H stretch region (2.7 µm), Zhu et al 5 the D2O bending region (8.5 µm), and Rivera-Rivera et al 6 the H2O bending region (6.3 µm).…”

“…McKellar 1 studied the C-O stretch region (4.7 µm), Oudjeans and Miller 4 the O-H stretch region (2.7 µm), Zhu et al 5 the D2O bending region (8.5 µm), and Rivera-Rivera et al 6 the H2O bending region (6.3 µm).…”

“…Wheatley and Harvey 12 computed a seven-dimensional surface (including CO stretching and water bending) using extrapolated intermolecular perturbation theory, and used it to determine second virial coefficients. More recently, Rivera-Rivera et al 6 reported various five-and six-dimensional potentials, beginning with ab initio calculations [CCSD(T)/aug-cc-pVTZ, or MP2/aug-cc-pVNZ] and then "morphing" for better agreement with experiment. Finally, Kalugina et al 13 computed a five-dimensional potential at a higher level of theory [CCSD(T)-F12a] and used it to calculate rotational excitation cross-sections for astrophysical applications.…”

“…The two tunneling components correspond to the two possible relative spin orientations of the H or D nuclei, aligned or anti-aligned, and in previous spectroscopic studies they have been labeled as the A and B components. [1][2][3][4][5][6] The ground state, A, has relative statistical weights 1 (H2O-CO) or 2 (D2O-CO) while the B state has weights 3 or 1. These tunneling states correspond to the nuclear spin modifications of the isolated water molecule: A correlates with para-H2O and ortho-D2O, and B with ortho-H2O and para-D2O.…”