Creation of groups of spatially correlated defects in a KBr crystal at 8 K

The creation spectrum of triplets of spatially correlated defects (F centre + self-trapped hole, V-K centre + interstitial halogen ion, I centre) was measured for the first time in a KBr crystal at 8 K using synchrotron radiation of 6-25 eV and highly sensitive luminescent methods. The spectrum of spatially correlated F and H centre creation by synchrotron radiation at 8 K was measured as well. The efficiency of F-V-K-I triplet creation is especially high at crystal irradiation by photons under the conditions of multiplication of electronic excitations when the absorption of one photon leads, respectively, to the formation of an electron-hole (e-h) pair and a secondary exciton (15.0-16.5 eV), or two e-h pairs (16.7-19.0 eV), or to the formation of a 3p(5)s cation exciton (19.5-20.5 eV). It is shown that the formation of an FVK-I triplet is caused by the recharging of a primary F-H pair by an e-h pair or by a free exciton.