EPR investigations on europium(II)-doped barium aluminate

High frequency EPR spectra of europium(II)-doped BaAl2O4 powder phosphor ha ve been analysed. Spectral simulation was carried out by a Fourier transfor m Monte Carlo method using an equation derived from the second-order pertur bation of the energy levels for S=7/2. It is found that the spectra can bes t be interpreted in terms of europium(ii) ions in two different sites. One quarter of the europium(ii) ions are located in a site with a \D\ of 0.345 cm(-1), and the remaining europium(ii) ions are in a site with a \D\ of 1.0 8 cm(-1). Estimated values of \E\ are equal to 1/3 \D\ and are independent of the sites. From the comparison of these EPR parameters with the XRD crys tallographic data we deduce that when europium is substituted for barium it s surroundings give rise to rearrangement.