ENERGY-LEVEL AND OSCILLATOR STRENGTH CALCULATIONS FOR ER3- A MOLECULAR-DYNAMICS BASED STUDY(Y2O3 )

A molecular dynamics (MD) based approach is being developed to calcula te energies and oscillator strengths for RE ions in various solid/liqu id/amorphous inorganic compounds. In this connection, the complete 364 X364 energy matrix for the Er3+ (4f(11)) electrons has been diagonaliz ed for different MD-generated environments. The importance of MD is em phasized. Configuration interaction (CI) effects are included in const ructing the energy matrix, since these have a significant influence on the derived absorption spectrum. The A, parameters have been calculat ed by direct summation over 100 multipole-expanded environments genera ted with MD. The various polarizabilities and shielding parameters use d have been calculated by ab initio methods. The derived energies and eigenvectors have been used to compute the oscillator strengths and th e corresponding spectra. Both electric-dipole and inhomogeneous dielec tric mechanisms have been considered in the oscillator strength calcul ation. The calculated Stark splittings and oscillator strengths for th e Stark-Stark level transitions agree well with experiment for Er3+:Y2 O3. The best agreement is obtained when consistent multipole contribut ions are included in the converged calculated crystal field. The metho d described above is important in predicting a priori laser related pr operties (radiative lifetimes, etc.) for potential host materials. (C) 1998 Elsevier Science S.A.