Electron Nuclear Double Resonance Of A Nearly Axial Rh2+ Center In Solution-Grown Nacl Crystals

Rh3+-doped NaCl single crystals grown from aqueous solution were studied with electron paramagnetic resonance and electron nuclear double resonance after irradiation at liquid nitrogen temperature. [RhCl6](4-) complexes with two next-nearest neighbor charge compensating vacancies have been detected. The two vacancy-Rh2+ axes make an angle of 90 degrees to each other and are perpendicular to the center symmetry axis. After warming the sample, this center with C-2 upsilon symmetry decays consecutively into two other [RhCl6](4-) centers reported earlier in Rh3+-doped NaCl and AgCl Bridgman crystals on the one hand, and/or in solution-grown NaCl:Rh3+ crystals irradiated at room temperature on the other hand. (C) 1998 American Institute of Physics.