Theoretical investigations of alkali metal: rare gas interaction potentials

Abstract

Alkali vapor lasers pumped by diode lasers are currently being investigated in several laboratories. One problem with this type of device is the poor matching of the broad linewidth of the pump source with the narrow absorption lines of the alkali atoms. A possible means for overcoming this difficulty is to use far-wing line broadening effects that are associated with alkali - metal rare gas interactions. This concept has recently been demonstrated for optical excitation of Cs-Ar dimers and collision pairs. Accurate data concerning the upper and lower state potential energy curves of M-Rg pairs are needed to evaluate the scaling possibilities for alkali metal rare gas dimer lasers. In addition to determining the details of the dimer absorption spectra, knowledge of the ground state potential also permits calculation of the number density of dimer pairs that will contribute to the absorption at a specific wavelength. In the present study we have used theoretical potential energy curves to predict equilibrium constants for the M + Rg ↔ MRg systems with M=Rb and Cs, and Rg=Ar, Kr and Xe. Excited state potential energy curves have been calculated for CsAr, and these data have been used to investigate the ability of first-principles calculations to predict the spectral properties of the Cs-Ar dimer.