The Vibrational Spectrum of Fluorochloroethyne FCCCl: Ab Initio Calculations and High Resolution Infrared Studies

摘要

The FCCCl molecule has been studied by ab initio methods and high resolution IR spectroscopy. Employing a TZ2Pf basis set the quadratic, cubic, and quartic force fields have been determined at the SCF and MP2 levels, and the equilibrium structure has been calculated. The vibrational and rovibrational parameters deduced from the force fields have guided the analysis of high resolution FTIR spectra of FCCCl in the v_1, v_2, 2 v_4 and v_4v_5 regions. Therefrom, ground, v_4 = 1 and v_5 = 1 rotational parameters have been determined by means of lower state combination differences. The 2v_4 (Σ~+) and v_4v_5 (Σ~+ and Δ) levels have been analyzed in detail, and anhar-monic perturbations disclosed with the help of the ab initio results. The available experimental data are in excellent agreement with the ab initio predictions.