F-centre production in alkali halides by electron-hole recombination and a subsequent [110] replacement sequence: a discussion of the electron-hole recombination

A model for F-centre production in alkali halides by ionizing radiation is discussed. The energy required for the formation of the defect is given to an anion in the radiationless recombination of an electron and a hole, which takes place via an exciton state. The primary products of this mechanism are negative ion interstitials and corresponding vacancies. The separation of the ion from the vacancy is achieved by a replacement sequence along a [110] direction. The radiationless transition is discussed in detail in this paper and its properties are seen to explain many hitherto inexplicable results of experiments in F-centre production. The replacement sequence is discussed in the following paper.