Noble Gas Optical Maser Lines at Wavelengths between 2 and 35μ

Abstract

This paper describes studies of the stimulated emission spectra of Ne, Ar, Kr, and Xe with Ge:Au, Ge:Cu, and Ge:Zn photodetectors. Term assignments are given (with alternatives specified in cases of ambiguities) for sixty newly observed or newly identified wavelengths of Ne, twenty-six of Ar, sixteen of Kr, and four of Xe. Only in the case of nine of the Ne lines ($5s-4p$) may the pumping of atoms to the upper maser level be attributed to energy transfer from metastable atoms of a different gas ($\mathrm{He} 2s{}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ atoms). For the other lines the excitation may occur through electron impact upon atoms in the ground state or in the lowest $s$ levels, or it may occur through processes of recombination and/or cascade. Some interesting regularities which appear among the observed lines are pointed out.