Optically induced F-centre aggregation in KCl

Both the changes in the optical absorption spectrum and the F*-centre emission thermoluminescence induced by F photostimulation at low temperatures in pure KCl samples previously irradiated at room temperature have been studied. It has been found that there is F aggregate centre formation during F photostimulation at 80 K without any clear F- centre formation. Aggregate centres are also formed at temperatures at which F*-centre emission glow peaks occur. It is concluded that the F* centre can act as mobile entity in F-centre aggregation processes. (author)