Electronic excitation energy transfer and nonstationary processes in KH{sub 2}PO{sub 4}:Tl crystals

Journal Article · Sat Apr 15 04:00:00 EDT 2017 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776117030050· OSTI ID:22756521

Pustovarov, V. A. ^[1]

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1. Ural Federal University named after the first President of Russia B.N. Yeltsin (Russian Federation)

We report the results of our experimental study and numerical simulation of the electronic excitation energy transfer to impurity centers under conditions where nonstationary processes take place in the hydrogen sublattice of potassium dihydrogen phosphate (KH{sub 2}PO{sub 4}) single crystals doped with mercury-like Tl{sup +} ions (KDP:Tl). We present the experimental results of our investigation of the decay kinetics of the transient optical absorption (100 ns–50 s) of intrinsic defects in the hydrogen sublattice of KDP:Tl obtained by pulsed absorption spectroscopy and the results of our study of the dynamics of the change in steady-state luminescence intensity with irradiation time (1–5000 s). To explain the transfer of the energy being released during electron recombination involving intrinsic KDP:Tl lattice defects, we formulate a mathematical model for the transfer of this energy to impurity Tl{sup +} luminescence centers. Within the model being developed, we present the systems of differential balance equations describing the nonstationary processes in the electron subsystem and the hydrogen sublattice; provide a technique for calculating the pair correlation functions Y(r, t) of dissimilar defects based on the solution of the Smoluchowski equation for the system of mobile hydrogen sublattice defects; calculate the time-dependent reaction rate constants K(t) for various experimental conditions; and outline the peculiarities and results of the model parametrization based on our experimental data. Based on our investigation, the dramatic and significant effect of a gradual inertial increase by a factor of 50–100 in steady-state luminescence intensity in the 4.5-eV band in KDP:Tl crystals due to the luminescence of mercury-like Tl{sup +} ions has been explained qualitatively and quantitatively.

• OSTI ID: 22756521
• Journal Information: Journal of Experimental and Theoretical Physics, Journal Name: Journal of Experimental and Theoretical Physics Journal Issue: 4 Vol. 124; ISSN JTPHES; ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTROSCOPY
BIOMEDICAL RADIOGRAPHY
COMPUTERIZED SIMULATION
CORRELATION FUNCTIONS
CRYSTAL DEFECTS
CRYSTALS
DOPED MATERIALS
ENERGY TRANSFER
EXCITATION
HYDROGEN
LUMINESCENCE
MATHEMATICAL MODELS
MATHEMATICAL SOLUTIONS
POTASSIUM PHOSPHATES
REACTION KINETICS
THALLIUM IONS
TIME DEPENDENCE