A new type of OH--based defect, in alkali halides, which was produced during the photo-ionization of F centers was studied by using optical, magneto-optical and magnetic resonance techniques. It was found that the defects were best described as consisting of a loosely bound electron which was trapped at a lattice site that was occupied by a single or paired OH- molecular defect. These centers exhibited an electronic absorption in the visible or near-infrared ranges, with a magnetically induced circular dichroism which was typical of F center type defects. An increased line-width of the magnetically induced circular dichroism-detected electron paramagnetic resonance signal, as compared to the F center that was caused by a stronger super-hyperfine interaction with its neighbors, suggested that the electron was less localized.

V.Dierolf, J.M.Spaeth: Materials Science Forum, 1997, 239-241, 461-4