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Mechanoluminescence; triboluminescence; colour centres; dislocations; alkali halides

The mechanoluminescence (ML) of NaCl, NaBr, NaF, LiCl and LiF crystals ceases at 105, 58, 170, 151 and 175°C respectively. Both the temperatureT_c at whichML disappears and the temperatureT_s required to induce a particular percentage of colouration decay in a given time, decreases with increasing nearest neighbour distance in alkali halide crystals. This perhaps suggests that similar processes cause the disappearance ofml in alkali halide crystals and the colouration decay in their microcrystalline powders. It is shown that mobile dislocations may cause the leakage of surface charge and the decay of colouration in microcrystalline powders.

B P Chandra¹ R D Verma^{1 2} M S K Khokhar^{1 2} S V Moharil^{1 3} K K Batra^{1 3} B T Deshmukh^{1 3}

1. Department of Physics, Rani Durgavati University, Jabalpur - 482 001, India
2. Department of Physics, Government Science College, Raipur - 492 002, India
3. Department of Physics, Nagpur University, Nagpur - 440 010, India

Published

December 1985

Manuscript received

9 May 1985

Manuscript revised

19 August 1985