EPR studies of the X-ray irradiated dithiophosphate salts

The powder EPR spectra of some ammonium and potassium salts of dithiophosphoric acid, (RO)₂P(S)SH, irradiated with X-rays at 77 K have been recorded and analyzed in respect to their distinguishable EPR-active components. In general each EPR spectrum is a superposition of isotropic and anisotropic features from a number of carbon- and phosphorus-centered radicals. Whereas carbon-centered radicals are practically isotropic the phosphorus-centered species exhibit threefold anisotropy with a large (700–800 G) isotropic³¹P hyperfine splitting. The identification of the latter is based on the magnitudes of the³¹P splitting as well as on the phosphorous 3p/3s spin densities ratio. The experimentally obtained EPR parameters of the studied radicals are refined using computer simulation procedure.