Abstracts 1997

Abstract of Publication No. 294

Karl W. Krämer, Hans U. Güdel and Robert N. Schwartz
Infrared-to-visible upconversion in LaCl3: 1% Er3+: Energy-level and line-strength calculations
Phys. Rev. B 56, 13830-13840 (1997)      Full Text (PDF)      DOI-Link     

Abstract: Single crystals of LaCl3:1%Er3+ were grown by the Bridgman technique. Er3+ substitutes for La3+ and has a site symmetry of C3h in LaCl3. Seventy-three energy levels of Er3+ were determined up to 45000 cm1 from absorption, excitation, and luminescence spectra measured over the temperature range 4.2-293 K. A correlated crystal-field analysis was done by fitting 16 atomic, four crystal-field, and one correlated crystal-field parameters to the experimental Stark levels. The fit is excellent with a standard deviation of 9.0 cm1. On the basis of the wave functions thus obtained the oscillator strengths for the transitions from the 4I15/2(1) ground state to all the levels up to 45000 cm1 were calculated by fitting seven complex Alt,p intensity parameters to 47 observed oscillator strengths. The intensity distribution among the crystal-field components was then calculated for the inter-excited-state transition 4I11/2 4F7/2 which plays an important role in an excited-state-absorption upconversion process.

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