Quantum-chemical ab initio study of the crystal-field and charge transfer energies of nanocrystalline Y2O3: Eu3+

The 4f energy levels and crystal-field parameters for several clusters representing the local coordination surroundings of Eu3+ in the bulk and nanocrystalline cubic Y2O3: Eu3+ crystals are obtained by using a method based on the combination of the DV-Xα calculation and the effective Hamiltonian method initialized by M.F. Reid et al. (J. Phys.: Condens. Matter, 2011, 23: 045501). The results are in reasonable agreement with the measured energy levels and the crystal-field parameters obtained from the least-square fitting. The charge transfer energies are also obtained for all the clusters from the DV-Xα calculation. The results indicate that, compared with the bulk Y2O3: Eu3+ crystal, the charge transfer band in the excitation spectra is red-shifted in the nanocrystal.

► Ab initio and effective Hamiltonian methods combined for energy level calculation. ► Crystal-field parameters and charge transfer energies derived for Y2O3: Eu3+. ► Energy levels of 4f(N) calculated and compared with experiments. ► Redshift of charge transfer band in the nanocrystals confirmed.