Theoretical simulation of V_K-centre migration in KCl. II. Phenomenological theory

An adequate theoretical basis is developed and presented for a nonstationary technique for the experimental detection of reactions in insulating crystals controlled by tunnelling recombination of mobile defects (hole centres) with electron centres. The effect of finite hop lengths of point defects in a crystalline lattice is carefully analysed. This method is based on measuring the inertial increase or decrease in the recombination luminescence intensity after a stepwise change of temperature (defect mobility). Theoretical analysis of the transient process observed experimentally for V_K centres in KCl:Tl crystals argues for their motion through 60 degrees rotations with the frequency factor S_t=4*10¹³ s^-1, very close to that obtained earlier in the optical dichroism studies.