Theoretical study of the infrared and ultraviolet spectrum of the radical F2CN

The aim of this work is to provide theoretical data in order to rationalize and complement experimental results previously obtained for the F2CN radic al. A vibrational analysis and a study of the first low-lying electronic st ates of this radical are reported. B3LYP and CCSD(T) wave functions are use d to calculate the optimized geometry and the potential function, while the electronic vertical transitions are studied from a CASPT2 approach. The vi brational analysis was carried out with a quartic force field and we show t hat the interpretation of the Fermi resonance observed near 1700 cm(-1) nee ds the inclusion of both cubic and quartic kinetic and potential terms in t he vibrational hamiltonian. (C) 2000 Elsevier Science B.V. All rights reser ved.