PHOTOLYSIS OF BRCN BETWEEN 193-NM AND 266-NM

The quantum state distributions of CN(X2Σ+) fragments from the photolysis of BrCN have been measured at several wavelengths between 193 and 266 nm. These distributions show that there is little or no vibrational excitation of the CN fragments for photolysis wavelengths below 230 nm. Above this wavelength, significant population is found in excited vibrational states. An explanation of this behavior is proposed and discussed. These results are shown to be in accord with recent theoretical ideas on excitation to a state where there is strong coupling between the rotational and translational degrees of freedom in the excited state. © 1987 American Chemical Society.