Hyperfine structure of EPR spectra of Cr⁵⁺ ions in irradiated sodium dichromate crystals

Abstract

E P R spectra are studied of X-irradiated sodium dichromate crystals grown from an aqueous solution by evaporation a t 31 O C . Doublet lines of EPR-absorption are attributed t o the Cr5+ ions in the (3-0:-and C i . 0~ radicals resulting from radiation decomposition of Cr 02-and being in the lattice in two unequivalent positions. Hyperfine structure caused by interaction of an unpaired electron with CrS3 nucleus were observed both a t liquid nitrogen and room temperatures. For the line, caused by Cr0:-radical, g, and A , directions coincide and angles both between A,, g , and A,, g , make up -25". The spectrum is described by usual spin Hamiltonian for S = l/z with following parameters ( T = 77 K): cni-l, IA,1 = 13.7