Predissociative T₁and S₁states of carbonyl chlorofluoride (ClFCO) and their photodissociation pathways

Abstract

The low-lying electronic states of carbonyl chlorofluoride (ClFCO) were studied using the coupled-cluster singles and doubles (CCSD) method. Highly reliable values for not only the geometrical parameters, but also the vibrational properties were generated for T 1 and S 1 as well as S 0 . Potential energy surfaces (PESs) of the dissociation of the three bonds were also obtained for each electronic state separately. We found that the T 1 and S 1 states are both vibrationally predissociative along the C-Cl bond dissociation channel, with barrier heights of only 0.13 and 0.23 eV, respectively. The relative energies for the S 1 state of the barriers to C-Cl and C-F bond dissociation are 4.93 and 6.13 eV, respectively, with respect to S 0 . These results suggest that a simple C-Cl bond dissociation pathway can explain the results of a previous photodissociation experiment with 235 nm (5.276 eV) light, in which only 'Cl þ FCO' fragments were observed.