CIF2 - STRUCTURE AND INFRARED-SPECTRA OF A WEAKLY BOUND TRIATOMIC MOLECULE

Using sophisticated ab initio methods, the equilibrium structure of th e ClF2 radical has been predicted to be bent, confirming previous expe rimental and theoretical work. The single, double and perturbative tri ple excitation coupled cluster level of theory along with a triple-zet a plus double polarization basis set gives the geometrical parameters r(e) = 1.756 angstrom and theta(e) = 151.8-degrees. At the same level of theory, harmonic vibrational frequencies were predicted to be 536, 243, and 568 cm-1 for the symmetric stretch, bend and asymmetric stret ch, respectively. In addition to this high level study of the harmonic vibrational frequencies, theoretical analyses of anharmonic terms hav e been included in order to help settle the controversy surrounding ex perimental assignments of the fundamental vibrational frequencies. Thi s research supports Mamantov's experimental assignment of the bending and symmetric stretching fundamental, over the experimental objections of Prochaska. The vibrational frequency splitting due to (ClF2)-C-37 was also studied indicating that only the splitting of the bending and asymmetric stretching modes should be readily observable experimental ly. Dipole moments and infrared (IR) intensities were also predicted.