Optogalvanic spectroscopy of twohyphen;photon dissociation of Tl2at 532 nm producing large population inversion between Tl(7thinsp;2S1/2) and (6thinsp;2P3/2) states

摘要

This paper reports the first time achievement of large population inversion between thallium 7thinsp;2S1/2and 6thinsp;2P3/2states through twohyphen;photon dissociation of pure Tl2molecules. The second harmonic of a Ndndash;YAG laser at 532 nm is used to cause twohyphen;photon absorption in Tl2from ground state Ouminus;to the repulsive state associated with the atomic 7thinsp;2Sand 6thinsp;2P1/2states. The relative population of the product atomic species is determined by using a tunable dye laser pumped by the third harmonic of a Ndndash;YAG laser. The dye laser beam focused for complete spatial and temporal overlap with the photodissociaiton pulse excites the product states to known atomic Rydberg states with subsequent ion detection. Prompt population inversion amounting to 100percnt; is achieved. It is shown that photodissociation transition is mediated through predissociation of the upper bound state to a repulsive state correlated with Tl(7thinsp;S1/2) in the region of large internuclear separation.