EXPERIMENTAL-EVIDENCE FOR SPATIAL CORRELATION BETWEEN F AND H CENTERSFORMED BY EXCITON DECAY AT LOW-TEMPERATURES IN KBR

Optical detection of electron paramagnetic resonance of F-H-centre pai rs created by low-temperature x-ray irradiation of KBr was performed v ia the magnetic circular dichroism of the optical absorption (MCDA) wh ereby cross-relaxation (CR) effects between the H and F centres were d etected in the MCDA of the F centres. A quantitative analysis of the C R effects yielded direct experimental evidence that all F and H centre s are spatially correlated after their low-temperature formation with a separation of four lattice sites along the [110] directions. A theor etical analysis of the CR result yields an estimate of the F-centre fo rmation time of 2 ps, in agreement with other experimental evidence, a nd also shows that the F-H separation obtained is the first stable F-H -centre pair configuration.