Analysis of the optical spectra and paramagnetic susceptibility of DyOF

Abstract

The optical absorption spectra of the rhombohedral DyOF were measured at selected temperatures between 9 and 300 K. The emission spectra of the ion in the LaOF and GdOF matrices were obtained at 77 K and room temperature. The energy level scheme of ( electron configuration) was simulated with a Hamiltonian of 20 parameters. The diagonalization of the energy matrices including simultaneously the free ion and crystal field (c.f.) interactions was carried out for the point symmetry of the site. Good correlation with an rms deviation of was obtained between the experimental and calculated energy level schemes of 153 Kramers doublets. The c.f. parameters show only slight distortion from symmetry. A comparison to , , , , and electron configuration) in other REOF matrices showed smooth evolution of the c.f. effect which was discussed in terms of the possible interactions involved. The x-ray powder diffraction pattern of DyOF between was analysed by the Rietveld profile refinement method. The structural data were used to calculate the c.f. parameters by the modified electrostatic point charge model yielding , and values close to the experimental ones, whereas the , , and values were too large. Using the experimental free ion and c.f. wave functions, the paramagnetic susceptibility of DyOF as a function of temperature was simulated. Above the Néel temperature (3.6 K), good agreement was obtained between the calculated and experimental susceptibilities in the paramagnetic range.