Variable temperature EPR studies of Cu²+ and VO²+ doped potassium dihydrogen citrate (C6H7KO7).

Electron paramagnetic resonance (EPR) studies of single crystals and powder samples of Cu(2+) and VO(2+) doped potassium dihydrogen citrate (PDHC) have been carried out at different temperatures. The temperature-dependant g and A values have been obtained for powder spectra of both Cu(2+) and VO(2+) ions in PDHC and the ground state of Cu(2+) ion has been determined. The powder spectra recorded for Cu(2+) ion in the temperature range 70-298 K are discussed with Jahn-Teller distortion. It is concluded that the g and A values of Cu(2+): PDHC show the static property at low temperatures. For all temperatures, the result g(//)<g(⊥)<g(e) of VO(2+): PDHC indicates that the unpaired electron exists in the d(xy) orbital.