Energy level and oscillator strength calculations for Er3+:Y2O3:: A molecular dynamics based study

A molecular dynamics (MD) based approach is being developed to calculate energies and oscillator strengths for RE ions in various solid/liquid/amorphous inorganic compounds. In this connection, the complete 364X364 energy matrix for the Er3+ (4f(11)) electrons has been diagonalized for different MD-generated environments. The importance of MD is emphasized. Configuration interaction (CI) effects are included in constructing the energy matrix, since these have a significant influence on the derived absorption spectrum. The A, parameters have been calculated by direct summation over 100 multipole-expanded environments generated with MD. The various polarizabilities and shielding parameters used have been calculated by ab initio methods. The derived energies and eigenvectors have been used to compute the oscillator strengths and the corresponding spectra. Both electric-dipole and inhomogeneous dielectric mechanisms have been considered in the oscillator strength calculation. The calculated Stark splittings and oscillator strengths for the Stark-Stark level transitions agree well with experiment for Er3+:Y2O3. The best agreement is obtained when consistent multipole contributions are included in the converged calculated crystal field. The method described above is important in predicting a priori laser related properties (radiative lifetimes, etc.) for potential host materials. (C) 1998 Elsevier Science S.A.