On the thermoluminescence build-up in molecular crystals

Measurements were performed on the thermoluminescence build-up of phenanthrene crystals UV excited at liquid N₂ temperature. Kinetic investigations show that the passage of electrons from excited molecules to traps takes place by means of a direct process, without the intervention of the conduction band states. Arguments are advanced to point out the possible role of Frenkel excitons in this process.