Microwave-Optical Double Resonance. Frequencies and Linewidths of Stimulated Emission Transitions in the A 2Π3/2 State of CN

Stimulated emission at microwave frequencies in the lambda doublet of the $A^2{\Pi }_{\text{3/2}}\text{, υ\hspace{0.17em}=\hspace{0.17em}10, J\hspace{0.17em}=\hspace{0.17em}}\frac{7}{2}$ level of CN has been reinvestigated. Observation of the increase in CN violet ${\mathrm{(B}}^2{\mathrm{\Sigma –X}}^2\mathrm{\Sigma )}$ emission caused by microwave pumping has allowed precise measurement of all seven of the allowed $\text{(ΔF\hspace{0.17em}=\hspace{0.17em}0,\hspace{0.17em}±\hspace{0.17em}1)}$ transitions between the hyperfine components of the lambda doublet. Effects of O₂ and SF₆ on electrical breakdown in the microwave cavity have been determined. Pressure dependence of the linewidths has been studied; comparison of these results with those of earlier experiments on CN suggests that the cross section for collisional energy transfer from the $A^2\Pi$ state to the $B^2\Sigma$ state is larger than that for rotational relaxation. The contribution of the optical radiative lifetime to the pressure‐independent width is demonstrated.