The electronic structure of an H-center

The electronic structure of a new type of color center, which is produced in KCl, KBr, and LiF crystals by X-irradiation at low temperatures, has been determined by electron-spin-resonance experiments. Crudely, this center can be described as a halogene−2 molecule-ion located in a halide-ion vacancy. The unpaired electron interacts strongly with the two nuclei of the moleculeion and weakly with two more halogen nuclei. All four nuclei lie in a straight row along a [110] axis. This paramagnetic center may be identical with the center that gives rise to the optical H-band, since in KCl it has the same production, bleaching, and symmetry characteristics.