Time-resolved studies of emission from I2(B3Πou+)

Abstract
The emission from I2(B3Πou+)→I2(X1Σ+ g)+hv has been monitored following the flash photolysis of CF3I. The study of the emission from this banded system using a rapid scan spectrometer shows that it commences approximately at the onset of the B–X continuum and that continuous emission resulting from the two-body recombination of I(52P½) and I(52P3/2), into which the B state resolves, is not important. Thus the emission in the banded region results from the production of I2(B) by recombination in the presence of a third body according to I(52P½)+ I(52P3/2)+ M →I2(B)+ M. There is no contribution from an inverse predissociation mechanism for which the energy barrier would be large. The rate equation for the concentration of I2(B) can be solved with a number of experimentally justifiable assumptions and the time-dependent concentrations of the ground state and excited atoms derived from previous observations on spin orbit relaxation. Thus the variation of the I2(B—X) emission, monitored at a single wavelength, can be correlated with the kinetics of I(52P½) and I(52P3/2).