EPR spectra of irradiated Na₂Cr₂O₇ · 2 H₂O crystals

Abstract

Abstract The EPR spectra of X‐irradiated Na 2 Cr 2 O 7 · 2 H 2 O crystals grown from the aqueous solution at room temperature are studied. Three groups of lines are detected, which marked conventionally as C 1 , C 2 and C 3 . Each of the C 1 and C 2 line groups is a superposition of two doublets. The lines are interpreted as due to the Cr 5+ ions in the distorted (stretched) oxygenous tetrahedron. The doublet structure is due to hyperfine interaction with nuclei of 1/2 spin which are protons of water. It is shown that the C 1 and C 2 line groups are due to the centers of the same type with different orientations in the lattice. The principal g ‐tensor values for these centres were as follows: g z = 1.916, g y = 1.978, g x = 1.986.