The absorption spectra of pure silver bromide and silver chloride crystals grown from the melt have been measured in and near the so-called "absorption edge," where the absorption coefficient increases very rapidly with frequency. The temperature-dependence of the absorption edge has also been investigated. More limited data have been collected on the absorption spectra of mixed AgBr—AgCl and AgBr—AgI crystals.

The requirements for an accurate measurement of the absorption edge in pure materials are discussed briefly, and it is estimated that the room-temperature data reported here are accurate to somewhat better than 10%. These new data are combined with some published measurements in an effort to obtain absolute absorption spectra for silver chloride and silver bromide over a large range of absorption coefficients.

• Received 10 February 1956

DOI:https://doi.org/10.1103/PhysRev.102.1519