Predissociative lifetimes of single rovibronic levels of the B 3Π0+(v′=3) state of ICl

Laser induced fluorescence (LIF) spectra of the 3–0 band of the B 3Π0+–X 1Σ+ system of I 35Cl and I 37Cl were observed for the first time by the use of a narrow bandwidth pulsed dye laser. Fluorescence lifetimes of the order of 1 ns have been successfully obtained for the rotational levels in v′=3 of the B 3Π0+ state. These measurements have shown that a new model of curve crossing has to be considered for the predissociation other than the well known B–Y crossing or the recently predicted heterogeneous crossing. On the assumption of Voigt profile for each hyperfine component, the line profile was analyzed to give the quadrupole interaction ‖ΔeQq‖ of approximately 0.065 cm−1 for v′=3. The asymmetry of the type of Fano’s profile was recognized on the observed line profile.