Lifetimes of the A 2π and B 2Σ States of the CN Radical

The lifetimes of the ${\mathrm{A\hspace{0.17em}}}^2\text{Π(v=10)}$ and ${\mathrm{B\hspace{0.17em}}}^2\text{Σ(v=0)}$ states of the CN radical have been measured from an analysis of the zero electric field limit linewidth of the level anticrossing spectrum. The measured value of ${\tau }_{\Sigma }\text{=39.4± 9.3}\mathrm{nsec}$ was found to be in reasonable agreement with the most recent phase shift measurement. The value of ${\tau }_{\pi }\text{=137± 45}\mathrm{nsec}$ was in serious disagreement with previous direct decay measurements on $\text{v≤ 9}$ vibrational levels, but in essential agreement with previous microwave and intensity measurements on the perturbed v=10 level.