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

Potential energy curves for the X (1)Sigma(g) (+) ground state and Omega=0(u) (+), 1(u) valence states and dipole moments for the 0(u) (+), 1(u)-X transitions are obtained in an ab initio configuration interaction study of Cl(2) including spin-orbit coupling. In contrast to common assumptions, it is found that the B (3)Pi(0(+)u)-X transition moment strongly depends on internuclear distance, which has an important influence on the Cl(2) 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(*)((2)P(1/2))/Cl((2)P(3/2)) branching ratio as a function of excitation wavelength. The calculated data are shown to be in good agreement with available experimental results. (c) 2004 American Institute of Physics.