High-resolution infrared spectroscopy of the CO · CO2 van der Waals molecule

Abstract

We report the infrared absorption spectrum of the CO · CO₂ van der Waals molecule in the region of the CO fundamental stretching vibration. By simultaneously fitting the observed spectrum with the previously observed microwave spectrum we have determined the upper-state spectroscopic constants. These are given as ν_o= 2148.241 44(14) cm^–1, Δν_o= 4.970 28(14) cm^–1, A′= 11 869.4(1.6) MHz, B′= 1874.68(40) MHz and C′= 1608.77(24) MHz. Using a model including electrostatic multipole and dispersion interactions we have constructed potentials for various structures. The experimentally observed structure is found to be the more stable.