Spectral properties of LiTaO₃:Pr³⁺under high hydrostatic pressure

Abstract

The high-pressure photoluminescence of the LiTaO 3 :Pr 3+ system obtained for the pressure range from ambient to 232 kbar at 20 K and ambient temperatures is presented. The observed pressure red shift of all spectral lines representing the f-f transitions is related to the changes in F 2 Racach integral and the spin-orbit coupling with pressure. To analyse the deexcitation kinetics and the dependence of the intensity of the 3 P 0 → 3 H 4 and 1 D 2 → 3 H 4 on the excitation wavelength and pressure we propose a model of a Pr 3+ trapped exciton with a hole localized at the Pr 3+ and an electron at the Rydberg states bounded by the long-range Coulomb potential of the hole.

Excited states dynamics under high pressure in lanthanide-doped solids

“…By analogy to atomic physics we call these states the Rydberg states, understanding that the similarity is related only to the spatial extension of the wave function and small ionization energies since atomic Rydberg states are characterized by much larger main quantum numbers [15]. Such an approach has been used for formulation of ITE concept [12,13,16] where the following Hamiltonian was proposed:…”

Impurity-trapped excitons: Experimental evidence and theoretical concept

“…Since the f electrons are well screened from the electric field of lattice ions, the pressure shifts of energies of the 4f n states are of a lesser order of magnitude than the pressure shifts of states belonging to the 4f nÀ1 5d 1 electronic configuration. The effect of pressure on exciton states in Pr 3+ -doped LiNbO 3 , LiTaO 3 [15,16,20], BaF 2 :Eu 2+ and Ba x Sr 1Àx F 2 :Eu 2+ [21,22] has been investigated recently.…”

Influence of high hydrostatic pressure on Eu2+-luminescence in KMgF3:Eu2+ crystal

“…The pressure causes an increase of the interaction of 4f n electrons with ligand electrons and diminishes the quantities of Racah parameters and spin-orbit coupling [13]. This is called the nephelauxetic effect [14,15] and is responsible for pressure-induced red shift of the 6 P 7/2 -8 S 7/2 luminescence.…”