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 A 1Π−X 1Σ+ 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 a′ 3Σ+(v=10) and k 3Π(v=4), are calculated. The v′=2 lifetime is 203± 12 nsec. The v′=0 lifetime, corrected for lengthening by triplet mixing, is 176± 14 nsec. Pressure broadening of the v′=2 signal is observed, and narrowing of the v′0 ones with pressure is attributed to radiation trapping.