INFRARED-SPECTRA OF MATRIX-ISOLATED CICO AND ABINITIO CALCULATION

Cl atoms and CO molecules were trapped in a solid Ar matrix at 16 K. The formation of ClCO was followed via its IR spectrum. The vibrational frequencies of (ClCO)-Cl-35-C-12-O-16 were observed at 1876.7, 570.1, and 334.6 cm-1. Experiments with different CO isotopomers were performed in order to confirm the assignment of the absorptions and to characterize the force field. The results extend and correct earlier data [M. E. Jacox and D. E. Milligan, J. Chem. Phys. 43, 866 (1965)]. With the help of quantum chemical calculations (UHF, MP2), the optimized ClCO bond angle was obtained to be 129.2-degrees. The computed bond lengths were determined to be 1.159 angstrom for C-O and 1. 807 angstrom for C-Cl. Based on force constant calculations, the C-Cl bond in ClCO was found to be extremely weak compared to that in Cl2CO.