Investigation Of Collisional Transfer In Excited Atoms By Applying Laser Absorption And Fluorescence Method

Collisional energy transfer in atoms and molecules can proved sighted into molecular interaction potential, energy distribute and new LASER development. Since the excited states of alkali atoms and molecules are low , it can be excited easyly, the fluorescence lie to infrared. Additionally since the density of alkali atomic energy levels approaches the point where almost continuous tuning may be achieved. They offer the possibility of newly high-power quasitunable lasers in the short-wave infrared.The domestic and international scholars are very interested in and pay much attention to it in recent years.In this thesis, we focus on studying collisional energy transfer process between excited states of alkali atoms and gas molecules by the technique of laser induce fluorescence spectroscopy and the theory of fluorescent rate equation .(1) The collisional energy transfer process Rb(5 PJ )+(He,N2) under gas cell conditions has been investigated. Using a rate equation model, we obtained the transfer rate coefficient for 5 P3 2→5P1 2transfer in collision with He is 2.23×10-12cm3s-1; with N2 is4.38×10-11 cm3s-1. The quenching rate coefficient out of the 5 PJ state is 5.45×10-11cm3s-1. The results are compared with other experiments.(2) Applying the CW laser absorption and fluorescence method, the cross sections for the fine structure mixing and quenching of the Cs(6P ) state, induced by collision with Ne atoms, have been measured.The result of this thesis areσ3/2→1 /2=(1.90±0.82)×10-19cm2 andσD=(8.97±3.85)×10-19cm2 .The precision of this experiment was enhanced because better dealed with radiation trapping.