Theoretical study of the UV photodissociation of Cl2: Potentials, transition moments, extinction coefficients, and Cl*/Cl branching ratio.

Potential energy curves for the X 1Σg+ ground state and Ω=0u+, 1u valence states and dipole moments for the 0u+, 1u-X transitions are obtained in an ab initio configuration interaction study of Cl2 including spin-orbit coupling. In contrast to common assumptions, it is found that the B 3Π0+u-X transition moment strongly depends on internuclear distance, which has an important influence on the Cl2 photodissociation. Computed energy curves and transition moments are employed to calculate the A, B, C←X extinction coefficients, the total spectrum for the first absorption band, and the Cl*(2P1/2)/Cl(2P3/2) branching ratio as a function of excitation wavelength. The calculated data are shown to be in good agreement with available experimental results. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]