Vibrational Assignment and Anharmonic Resonance Analysis of the Dispersed Fluorescence and Stimulated Emission Pumping Spectra of DFCO (S 0 ) up to 9000 cm-1
Dispersed fluorescence and stimulated emission pumping spectra of jet-cooled DFCO from the 2(1) 6(2) , 5(1) 6(4) , 2(1) 5(1) 6(2) , and 5(1) 6(6) vibrational states of S 1 are presented up to 9000 cm-1 . Progressions are assigned primarily to vibrational states with excitation in the Franck-Condon active modes nu2 , nu5 , and nu6 . The spectrum is perturbed by a 266 (nu2 approximately 2nu6 ), a 233 (nu2 approximately 2nu3 ), and a 3566 (nu3 + nu5 approximately 2nu6 ) anharmonic resonance. These three resonances are increasingly important at high vibrational energies, thus explaining the complexity of the DFCO spectrum compared to that of HFCO. Seventy-five vibrational states are assigned as eigenstates of a 266, 233, and 3566 anharmonic resonance Hamiltonian. The rms deviation in the calculated energies is 1.2 cm-1 . Harmonic frequencies and anharmonic constants are reported. These are compared to constants derived from ab initio potential energy surfaces.