Journal of Physical Chemistry A, Vol.117, No.46, 11906-11914, 2013
Near-IR Spectrum of NO(X-2 Pi)-Xe: A Joint Experimental Theoretical Investigation
Employing the method of constant photon energy sum (CONPHOENERS) scans, we measure the near-IR spectrum of NO Xe in the region of the first vibrational overtone of the NO monomer. Three bands are detected, which are assigned as the origin band located at 3722.60 cm(-1) and as bands with excitation of one quantum of z-axis rotation (3726.07 cm(-1)) and one quantum of bending vibration (3739.02 cm(-1)), respectively. The partially resolved rotational and electronic fine structures of the bands are analyzed with the help of a full quantum mechanical boundstate calculation using the ab initio potential energy surfaces of Klos et al. (J. Chem. Phys. 2012, 137, 014312/1-014312/14). We perform a linear least-squares fit to the calculated energy levels to determine a set of spectroscopic constants that describe not only the overall rotation of the complex but also the electrostatic splitting due to the sum potential and the P-type doubling due to the difference potential. Using these results as guidance, we are able to simulate the experimental spectra. The comparison with the results from the theoretical treatment confirms the high quality of the ab initio treatment. The position of the excited bands is predicted with sub-wavenumber accuracy. Also, the rotational constants for all bands are found within less than 5%. Some differences are found for the amount of P-type doubling, which is overestimated by the theoretical treatment. Constants for the electrostatic splitting are in reasonable agreement for the origin band. Larger deviations are found for the vibrationally excited band, which points toward some inaccuracies in the potential energy surfaces.