| Abstract |
Three-dimensional potential energy and dipole moment surfaces have been calculated for the 24 electron triatomics O3, CF2, NO2-, and NF2+ using complete active space self-consistent field wave functions (CASSCF) and a basis set of 87 (99 for NO2-) contracted Gaussian-type orbitals (cGTOs). The analytical potential energy functions (PEFs) have been used in perturbation and variational calculations of anharmonic spectroscopic constants and vibrational energy levels. The results for O3 and CF2 are compared to the available experimental data, and predictions of the rotational and vibrational spectra of NO2- and NF2+ have been made by comparison to these species. The equilibrium geometries of NO2- and NF2+ are predicted to be r(e) = 1.260 angstrom, theta-e = 116.5-degrees and r(e) = 1.242 angstrom, theta-e = 108.0-degrees, respectively. The fundamental vibrational frequencies (nu-1,nu-2,nu-3) and absolute band intensities (at 300 K) of these two ions are predicted to be 1286 cm-1/31 cm-2 atm-1, 782 cm-1/13 cm-2 atm-1, 1232 cm-1/2900 cm-2 atm-1 (NO2-) and 1272 cm-1/181 cm-2 atm-1, 711 cm-1/25 cm-2 atm-1, 1210 cm-1/1230 cm-2 atm-1 (NF2+). Band intensities for several low-lying vibrational transitions have been calculated for all four species from the CASSCF dipole moment functions, and comparisons to experiment have been made for O3 and CF2. |