Observation of the Forbidden Magnetic Dipole Transition 6 exp 2 p/sub 1/2/ Implies 7 exp 2 p/sub 1/2/ in Atomic Thallium

摘要

A measurement of the 6 exp 2 P/sub 1/2/ implies 7 exp 2 P/sub 1/2/ forbidden magnetic dipole matrix element in atomic thallium is described. A pulsed, linearly polarized dye laser tuned to the transition frequency is used to excite the thallium vapor from the 6 exp 2 P/sub 1/2/ ground state to the 7 exp 2 P/sub 1/2/ excited state. Interference between the magnetic dipole M1 amplitude and a static electric field induced E1 amplitude results in an atomic polarization of the 7 exp 2 P/sub 1/2/ state, and the subsequent circular polarization of 535 nm fluorescence. The circular polarization is seen to be proportional to (M1)/(E1) as expected, and measured for several transitions between hyperfine levels of the 6 exp 2 P/sub 1/2/ and 7 exp 2 P/sub 1/2/ states. The result is (M1) = -(2.11 +- 0.30) x 10 exp -5 parallel bar e parallel bar dirac constant/2mc, in agreement with theory. (ERA citation 02:027641)