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Optical materials; crystal growth; optical spectroscopy; thermal analysis.

Energy transfer process at room temperature for cerium (sensitizer) oxalate single crystals doped with different concentrations (10, 13, 15, 17 and 20%) of praseodymium ions (activator) grown by hydro silica gel method has been evaluated. The analysis of energy level diagrams of cerium and praseodymium ions indicates that the energy gap between the sensitizer and the activator ions varies in a small range suggesting a possible energy transfer from the Ce³⁺ to Pr³⁺. The emission and absorption spectra of these crystals were recorded. The overlapping of the absorption spectra of Pr³⁺ and emission spectra of Ce³⁺ at wavelengths 484 and 478 nm, respectively, strongly supports the possible energy transfer process in this system. From the absorption spectra, oscillator strength, electric dipole moment, branching ratio and Judd–Ofelt parameters of this system were evaluated by least square programming. The quantum efficiency, energy transfer probabilities and thermal properties have been studied.

R Pragash¹ Gijo Jose¹ N V Unnikrishnan¹ C Sudarsanakumar¹

1. School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, India

Published

July 2011

Manuscript received

7 December 2009

Manuscript revised

12 August 2010