Ultraviolet Absorption of Alkali Halides

The absorption spectra of evaporated films of the alkali halides, with the exception of LiF, have been measured at room temperature and 80^∘{}K in the region from 1100 A to 2500 A. The spectra are rather complex at low temperature, but agree fairly well with current theory concerning the multiplicity and grouping of the exciton peaks. In addition, a shoulder has been found in many of the spectra, similar to the ones previously seen and associated with the band-to-band transition in the alkali iodides.