PULSED EPR SPECTROSCOPY OF THE V-KA CENTER IN CAF2-NA

An EPR study of the self-trapped hole center (V-KA center) in Na-doped single-crystal CaF2 is reported. A five-component hyperfine-interacti on tensor was used for the first time to describe EPR spectra adequate ly. The parameters of the electron spin Hamiltonian of the V-KA center , the tensors of ligand hyperfine interaction with all nearest-neighbo r nuclei, and constants of quadrupole interaction with the Na nucleus have been determined. The structure of the center has been unambiguous ly established from the results obtained, and the mechanisms of its fo rmation are discussed. (C) 1998 American Institute of Physics. [S1063- 7834(98)01109-5].