Hanle Effect Measurement of the Lifetime of the A 1π State of CS

Four different atomic emission lines which coincide with absorption lines of the $\mathrm{A}{\hspace{0.17em}}^1{\mathrm{\Pi -X\hspace{0.17em}}}^1{\Sigma }^{+}$ system of CS are used to excite and make Hanle effect measurements on the A ¹π levels: v′=2, J′=6; v′=0, J′=8; and v′=0, J′=12. Each level's signal width in the limit of zero pressure determines its radiative lifetime if the g factor is known. For v′=2 a pure ¹π g factor is used; the g factors of the v′=0 levels, perturbed by interactions with $\mathrm{a}{\mathrm{\prime \hspace{0.17em}}}^3{\Sigma }^{+}\text{(v=10)}$ and $\mathrm{k}{\hspace{0.17em}}^3\text{Π(v=4)}$ , are calculated. The v′=2 lifetime is $\text{203± 12\hspace{0.17em}}\mathrm{nsec}$ . The v′=0 lifetime, corrected for lengthening by triplet mixing, is $\text{176± 14\hspace{0.17em}}\mathrm{nsec}$ . Pressure broadening of the v′=2 signal is observed, and narrowing of the v′0 ones with pressure is attributed to radiation trapping.