An application of the continuous wave four-wave mixing technique for studyi
ng the nature of metastable centers in semiconductors is presented. The res
ults of measurements of the four-wave mixing scattering efficiency dependen
ce on the intensity of the write beams for CdF2 crystals doped with In or G
a are presented and theoretically explained. It is also shown that the obta
ined results can be used for identification of the sign of the Hubbard corr
elation energy of metastable centers in semiconductors. (C) 2001 American I
nstitute of Physics.