High resolution infrared spectroscopy and structure of CO-N2O

The infrared spectrum of the van der Waals complex CO-N2O has been recorded in the region of the nu(3)N(2)O monomer vibrational band using a diode laser absorption spectrometer which incorporates a multipass cell and a pulsed jet. The spectrum has been completely analyzed using a normal asymmetric rotor Hamiltonian and the effective molecular constants are accurately determined for both ground and excited vibrational states. The band origin of CO-N2O is observed to shift toward higher wavenumber from the N2O monomer by 2.90540 cm(-1). With the aid of an intermolecular potential calculation, we are able to determine that the complex has a T-shaped configuration with the CO forming the leg of the T and the C atom of the CO molecule pointing to N2O. The structural parameters are R-cm'' = 3.8707(3) Angstrom, theta(N2O) = 80 degrees +/- 5 degrees, and theta(CO) = 20 degrees +/- 5 degrees. (C) 1997 Academic Press.