Knowledge Bank

Single crystal growth methods have been used to incorporate $SH-$ and $SD-$ impurities in a series of Na, K and Rb halides. In the infrared spectra, obtained at temperatures ranging from room temperature down to liquid helium, the vibrational fundamentals, first overtones, and librational modes of the isolated ionic impurities have been identified, as well as vibrational absorptions due to impurity pairs. The spectra of $SH-$ differ in many respects from those of $OH-$; for example, with a given halide, the $SH-$ fundamental frequency is highest in the Rb salt. Interpretation of the spectra will be discussed.