Journal of Chemical Physics, Vol.104, No.7, 2488-2496, 1996
Continuous Slit-Jet Infrared-Spectrum of the Co-N-2 Complex
The weakly bound complex CO-N-2 has been studied in the 4.7 mu m infrared region of the CO stretching vibration using a continuous slit-jet supersonic expansion and a tunable diode laser spectrometer. A total of 152 lines were observed and assigned to four connected subbands with K = 0 <-- 1, 0 <-- 0, 1 <-- 0, and 2 <-- 1, and to one unconnected subband with K = 1 <-- 1. Analysis of these bands yielded K-state origins, rotational parameters, and centrifugal distortion parameters. The effective intermolecular separation for the complex in its ground state was found to be 4.025 Angstrom, and predictions of rotational frequencies were made to aid in the search for CO-N-2 microwave transitions. The spectra observed were surprisingly simple and well behaved, to the extent that they could virtually be ascribed to a (fictitious) complex of CO with a rare gas atom having a mass of 28 a.m.u. This simplicity may be explained by postulating that the N-2 undergoes relatively free internal rotation in the complex. All but one of the observed bands involve levels which correlate with the rotationless J = 0 state of ortho-N-2. Further spectroscopic work in the infrared and microwave regions should be combined with theoretical studies in order to learn more about the orientational structure and intermolecular potential of this atmospherically relevant system.
Keywords:DIODE-LASER;VANDERWAALS COMPLEX;4.7-MU-M REGION;SUPERSONIC JET;CO DIMER;SPECTROSCOPY;NITROGEN