Link between optical spectra, crystal-field parameters, and local environments of Eu{sup 3+} ions in Eu{sub 2}O{sub 3}-doped sodium disilicate glass
- School of Physical Sciences, University of Kent, Canterbury CT2 7NH (United Kingdom)
- Department of Physics and Astronomy and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch 8140 (New Zealand)
- Department of Science and Environmental Studies, Hong Kong Institute of Education, 10 Lo Ping Road, Tai Po, New Territories, Hong Kong (Hong Kong)
- Laboratorio di Chimica dello Stato Solido, DB, Universita di Verona, INSTM, UdR Verona, I-37134 Verona (Italy)
Rare-earth-doped glasses are key materials for optical technology due to the luminescent properties of 4f{sup n} ions. The crystal-field model describes the effect of local environment on transitions between 4f electrons. We present a detailed modeling study of the optical spectra of sodium disilicate glass, 33Na{sub 2}O{center_dot}67SiO{sub 2}, doped with 0.2% and 1.0 mol%Eu{sub 2}O{sub 3}. This study uses very large molecular dynamics models with up to 100 Eu{sup 3+} ions, the superposition model for covalent and overlap effects on crystal-field parameters, and realistic values for homogeneous linewidth broadening. The simulated spectra are in reasonable agreement with experiment. The trends in {sup 7} F{sub J} energy levels across different Eu{sup 3+} ion sites have been examined and a very detailed analysis is presented that looks at how features of the spectra are related to features of the local environment of Eu{sup 3+} ions. Increasing the crystal-field strength S{sub total} causes the {sup 7} F{sub 0} energy level to decrease and causes the splitting of {sup 7} F{sub J} manifolds to increase, and this is due to increasing mixing of 4f wave functions. To a reasonable approximation the crystal-field strength components S{sub k} depend on angular positions of ligands independently of distances to ligands. The former are seen to be more significant in determining S{sub k}, which are closely related to the rotationally invariant bond-orientational order parameters Q{sub k}. The values of S{sub 2} are approximately linear in Q{sub 2}, and the values of Q{sub 2} are higher for fivefold than sixfold coordinated rare-earth ions. These results can be of importance for efforts to enhance the local environment of rare-earth ions in oxide glasses for optical applications.
- OSTI ID:
- 21596863
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 84, Issue 10; Other Information: DOI: 10.1103/PhysRevB.84.104206; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
APPROXIMATIONS
CORRELATIONS
CRYSTAL FIELD
DOPED MATERIALS
ENERGY LEVELS
EUROPIUM IONS
EUROPIUM OXIDES
GLASS
INCLUSIONS
LUMINESCENCE
METALLIC GLASSES
MIXING
MOLECULAR DYNAMICS METHOD
ORDER PARAMETERS
SIMULATION
SPECTRA
WAVE FUNCTIONS
CALCULATION METHODS
CHALCOGENIDES
CHARGED PARTICLES
DIMENSIONLESS NUMBERS
EMISSION
EUROPIUM COMPOUNDS
FUNCTIONS
IONS
MATERIALS
OXIDES
OXYGEN COMPOUNDS
PHOTON EMISSION
RARE EARTH COMPOUNDS