Knowledge Bank

The electronic predissociation $CN(A2\Pi 3/2,v=3)-Ne\to CN(X,v=7)+Ne$ was characterized using sequential pulse $B\leftarrow A\leftarrow X$ excitation of the complex. Pump and probe lasers were fixed on specific complex features, and the intensity of the OODR fluorescence signal was monitored as a function of the delay between the laser pulses. Single exponential fits to these data yielded lifetimes in the range of 100-170 ns for A state rotational levels in the range $1/2\le j\le 9/2$. Radiative decay occurs with a lifetime of $\approx 6 $ , and makes a negligible contribution to the decay of the CN(A)-Ne levels examined. Within the experimental error lilmits, the predissociation rates were linearly dependent on J(J+1). This behavior is characteristic of a mechanism that involves Coriolis coupling. However, the decay rate does not approach the radiative rate at the hypothetical J=0 limit, and it is clear that the dominant predissociation channel does not depend on Coriolis coupling. Extrapolation of the decay rate yields a lifetime of 175 ns for the non-rotating complex. This value is comparable to the lifetime of 91 ns reporting for CN(A, $v=3$) isolated in solid Ne matrix. Experimental details and a theoretical analysis of the predissociation mechanism will be presented.