Measurement of velocity dependence of collisional excitation transfer applying resonant doppler-free 2-photon laser spectroscopy

Abstract

The velocity dependence of the collisional excitation transfer process within the fine structure of the Li 3p 2P 1 2 , 3 2 levels due to the noble gases He and Ne have been measured. The relative velocities correspond to a range of 750 K (actual cell temperature) to about 5000 K. The experiment, performed in a thermionic diode, is based on the velocity selective laser excitation of Li atoms within the Doppler profile and probing the velocity group in the excited as well as the collisional populated level with a second laser. In a thermionic diode with improved sensitivity, collision processes of velocity groups can be studied which correspond to temperatures larger than 15000 K.