PRE-DISSOCIATIONS IN THE B3PI-0+ STATE OF I35CL AND I37CL

Profiles of lines in the 3-1 and 2-0 bands of the B 3Π 0+←X 1Σ+ system of I35Cl and I37Cl vapor, as well as in several fragmentary P and R branches associated with an adiabatic B′ state, have been recorded using a Fabry-Perot interferometer spectrometer. The potential curves of the B state, and of the adiabatic B′ state formed by an avoided crossing near 3.6 Å and 18 140 cm-1 between the B state and a repulsive Y O + state, have been determined using the intermediate coupling model of Child. Linewidths in υ = 2 of the B state are observed to be 0.034 cm-1, independent of J and of isotopic composition; however, linewidths in υ = 3 are broader, corresponding to predissociative lifetimes in the subnanosecond range, and are found to oscillate as a function of J. The major features of the observed linewidth pattern can be explained in terms of analytical approximations developed by Child and co-workers, and provide evidence for a second curve crossing, near 2.94 Å and 17975 cm -1, of the B state and an Ω = 1 state. © 1979 American Institute of Physics.