Interaction potential energies and quasi-continuum vacuum UV emission of rare-gas-alkali ionic eximers

摘要

An ab initio calculation of the potential energies was made for the electronic states of ionic excimer molecules consisting of rare gases (Rg=Ne,Ar,Kr and Xe) and alkali metals (A=K AND Rb). The calculation included the ground 1~1∑＋, which correspond to the Rg(~S)＋A(~1S) and Rg＋(~2P)＋A(~2S) separate limits, respectively. The calculated results predict that the emission based on transitions from the 2~1∑＋(υ'=0) states to the higherυ" levels of the 1~1∑＋ states is characterised by the highest relative transition probabilities, which are promising for lasing in the vacuum and extreme ultraviolet (VUV/XUV) SPECTRAL RANGES. Moreover, bound-free VUV emission bands were observed for electron-beampumped gas mixtures of Xe or Kr with a hot Rb or Cs alkali vapour. The observed four emission bands were assigned to the 2~1∑＋ transitions in the rare-gas-alkali ionic excimers Xe＋Rb, Kr＋Rb, Xe＋Cs, and kr＋ Cs, respectively.