Abstract
Single crystals of Ca, Sr, and Ba have been colored by x rays (150 kv) and high-energy electrons (2.5 Mev). Five color-center bands in Ca and Sr and nine in Ba have been observed in the spectral region between 0.175 and 0.8 μ. At room temperature the bands in Ca are well resolved, while those in Sr and Ba overlap. At -190° and -255°C the bands sharpen but generally do not shift, except the 580-mμ band in Ca which shifts toward longer wavelengths. Photochemical bleaching of the strongest band shows a certain influence on the others. Three bands could be correlated to the Mollwo relation with the exponent 3.85. A possible correlation of the absorption bands to certain models is discussed.
- Received 14 July 1960
DOI:https://doi.org/10.1103/PhysRev.120.1162
©1960 American Physical Society