Double-Donor—Acceptor Pair Lines and the Chemical Identification of theI1Lines in CdS

Abstract
We report a new type of pair-line spectrum, namely, the recombination of a double neutral donor with a shallow neutral acceptor. An isotope shift in this pair-line spectrum proves that the acceptor is lithium. This identification, together with the results of chemical doping experiments, provides strong evidence that the I1 lines in CdS are due to Li and Na.