Use of polarized optical absorption to obtain structural information for Na1/Nd31 b9-alumina

• Part of the optical absorption spectrum is calculated for the Nd31-doped Na1 b9-alumina using a moleculardynamics-~MD! based approach. The Judd/Ofelt ~J/O! theory is modified ~and several approximations removed! to treat polarized transition intensities for rare-earth ions in a solid host. Stark-level energies and eigenfunctions of the ground state ~4I9/2! and excited multiplets (4F3/2,2P1/2) are also calculated for the local environments involved. Energies and polarized transition intensities between individual Stark levels are thus calculated simultaneously for several hundreds of MD-generated environments; summation gives the total bandshape. A high proportion of Beevers-Ross-site occupation ~.50%! is indicated for low Nd31 concentrations in b9-alumina. The contrary is observed experimentally for high Nd31 concentrations, i.e., then midoxygen site occupation dominates. It is demonstrated that ions in different local environments contribute differently to the absorption spectrum and, particularly, how the polarization of the various transitions changes for ions occupying different sites. Temperature dependence aspects are also considered

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

absorption

rare earth

Electrical engineering, electronics and photonics

Elektroteknik, elektronik och fotonik

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)