The Vibrational Spectrum of Fluorochloroethyne FCCC1: Ab Initio Calculations and High Resolution Infrared Studies

Abstract

AbstractThe FCCC1 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 FCCC1 in the v1, v2, 2v4 and v4 v5 regions. Therefrom, ground, v4 = 1 and v5 = 1 rotational parameters have been determined by means of lower state combination differences. The 2v4 (Σ+) and v4v5 (Σ+ and Δ) levels have been analyzed in detail, and anharmonic perturbations disclosed with the help of the ab initio results. The available experimental data are in excellent agreement with the ab initio predictions.