Biological and Chemical Physics


Relative state-to-state rotationally inelastic cross sections for excitation of carbon monoxide by hydrogen were measured in a crossed molecular beam experiment at collision energies 795, 860, and 991 cm-1. The results are compared to predictions of a recent ab initio potential energy surface [J. Chem. Phys. 108, 3554 (1998)]. The agreement is very good. A comparison with older data on thermally averaged total depopulation cross sections [Chem. Phys. 53, 165 (1980)] indicates that the absolute magnitudes of the cross sections predicted by the surface are too high. The CO excitation is dominated by collisions that are elastic in H2 rotation, and the collision dynamics are very similar for different rotational levels of hydrogen.


Original Citation: Stiliana Antonova, Antonis P. Tsakotellis, Ao Lin, and George C.McBane. State to state rotational excitation of CO by H2 near 1000 cm−1 collision energy. J. Chem. Phys., 112:554–559, 2000.