Photo- and thermochemical reactions with participation of Br3- centres in X-rayed KBr

The photodissociation of Br3- centres (H', V4, V2, D3 centres) at 4.2 K, created by X-ray in pure and doped KBr at 4.2 to 300 K, and the thermorestoration of Br3- centres from their photodestruction products are investigated by the absorption method. It is shown that V/sub F/ and H centres are created as a result of photodissociation of the high-temperature Br3- centres (V4, V2, D3) but only H centres arise during the photodissociation of low-temperature H' centres. It is concluded that at temperatures above 80 K the Br3- ion occupies regular cation and anion sites, i.e. X-radiation creates both cation and anion vacancies. At temperatures below 80 K the Br3- ion has interstitial bent configuration, indicating that cation vacancies are not created. (author)