Recently there was a discussion concerning whether an electron in the conduction band was localized or delocalized. The back and forth arguments seemed inconclusive, difficult to follow (too brief too couched in jargon/unrealistic models) and ended in something close to insults back and forth. Lets assume for a moment that the electrons in the conduction band are completely delocalized. In thermoluminescence kinetics, an electron can be trapped in a state created by a defect and the energy level of the trapped electron is in the forbidden band. The electron is considered localized (at least in the very near vicinity of the defect). Following excitation, (usually either thermal or optical ) the electron receives sufficient energy and is ejected to the conduction band. Thermoluminescence theory then assumes that the electron will become a delocalized entity. Any ideas on the time or diffusion length in the delocalization process ??? Have any realistic calculations been carried out ? On semi-conductors, on insulators (very large band gaps). Please try to give an answer in as intuitive a manner as possible (I realize that this may be difficult - but do your best).