Energy Levels Of Pr Research Articles

High pressure luminescence and time resolved spectra of LiNbO3:Pr3+

Emission, luminescence excitation spectra and photoluminescence spectra at high pressure of LiNbO 3 crystal doped with 0.5% Pr 3+ are presented. Hydrostatic pressure up to 135kbar was applied with a diamond anvil cell (DAC). We observed the small red shift of the luminescence related to 1 D 2 → 3 H 4 transition equal to 0.08nm/kbar. Additionally, at higher pressure, the 1 D 2 emission was considerably quenched and its lifetime was shortened. This was explained as being due to the decrease of the energy of the exciton bound to the Pr 3+ ion with increasing pressure and nonradiative depopulation of the 1 D 2 state. Full Text: PDF References H. Laro, M. Voda, F. Jaque, J.E. Munoz-Santiuste, J. Garcia-Sole, "Polarized absorption of Nd 3+ in LiNbO 3 : Effect of MgO codoping", J. Appl. Phys. 77, 5929 (1995) [CrossRef] A. Lorenzo, L.E. Bausa, J. Garcia-Sole, "Optical spectroscopy of Pr 3+ ions in LiNbO 3 ", Phys. Rev. B. 51, 16643 (1995) [CrossRef] A. Lorenzo, E. Camarllo, H.S. Maurrieta, S. Alvarez, V.G. Hemandez, M. Voda, F. Jaque, J. Garcia-Sole, "Optical spectroscopy of Dy 3+ ions in LiNbO 3 ", Opt. Matter. 5, 251 (1996) [CrossRef] M. Malinowski, P. Myziak, R. Piramidowicz, I. Pracka, T. Łukasiewicz, B. Surma, S. Kaczmarek, K. Kopczyński, Z. Mierczyk, "Spectroscopic and laser properties of LiNbO 3 :Dy 3+ crystals", Acta Phys. Pol. 90, 181 (1996) A. Lorenzo, L.E. Bausa, J.A. Sanz, J. Garcia-Sole, "Optical absorption intensities and fluorescence dynamics of Ho 3+ ions in LiNbO 3 ", J. Phys.: Cond. Matter 8, 5781 (1996) [CrossRef] J. Amin, B. Dusardier, T. Schweizer, M. Hempsead, "Spectroscopic analysis of Er 3+ transitions in lithium niobate", J. Lumin. 69,17 (1966) [CrossRef] L. Nunez F. Cusso, "Polarized absorption and energy levels of LiNbO 3 :Tm and LiNbO 3 (MgO):Tm", J. Phys.: Cond. Matter. 5, 5301 (1993) [CrossRef] Z. Łuczyński, T. Łukasiewicz, I. Pracka, B. Surma, M. Malinowski, "Emission properties of LiNbO 3 :Tm 3+ ", J. Appl. Spectr. 62, 66 (1995) A. Lorenzo, H. Jaffrezic, B. Roux, G. Boulon, L.E. Bausia, J. Garcia-Sole, "Lattice location of Pr3+ ions in LiNbO 3 ", Phys. Rev. B 52, 6278 (1995) [CrossRef] R. Piramidowicz, I. Pracka, W. Woliński, M. Malinowski, "Blue-green emission of Pr 3+ ions in LiNbO 3 ", J. Phys.:Cond Matter 12, 709 (2000) [CrossRef] J.E. Munoz-Santiuste, A. Lorenzo, L.E. Bausa, J. Garcia-Sole, "Crystal field and energy levels of Pr 3+ centres in LiNbB 3 ", J. Phys.: Cond Matter 10, 7653 (1998) [CrossRef] D.S. McClure, C. Pedrini, "Excitons trapped at impurity centers in highly ionic crystals", Phys. Rev. B 32, 8465 (1985) [CrossRef] W. Gryk, B. Kukliński, M. Grinberg, M. Malinowski, "High pressure spectroscopy of Pr 3+ in LiNbO 3 ", J. Alloy. Comp. 380, 230 (2004) [CrossRef] W. Gryk, D. Dyl, M. Grinberg, M. Malinowski, "High pressure photoluminescence study of Pr 3+ doped LiNbO 3 crystal", Phys. Stat. Sol. C 2, 188 (2005) [CrossRef]

Parameterized analysis of the ab initio calculation of Pr 3+ energy levels

The energy levels of Pr 3+ ions from various relativistic coupled-cluster calculations and from measurements are studied based on the parametrized semi-empirical Hamiltonian. The results show that a set of energy levels obtained from ab initio calculation may be converted into a set of semi-empirical parameters. Parameter values have advantages because the interpretation of the interaction mechanisms is simpler and they may be easily combined with semi-empirical methods. We propose calculation of parameters by combining relativistic coupled-cluster theory with many body perturbation theory instead of calculation of energy levels directly in future ab initio calculations.

Structure and properties of the pure and Pr 3+-doped Ge 25Ga 5Se 70 and Ge 30Ga 5Se 65 glasses

The Ge 25Ga 5Se 70 and Ge 30Ga 5Se 65 pure and Pr 3+-doped glasses were prepared by direct synthesis from elements and PrCl 3. It was found that up to 1 mol% PrCl 3 can be introduced in the Ge 25Ga 5Se 70 and Ge 30Ga 5Se 65 glasses. Both types of glasses with overstoichiometric and substoichiometric content of Se were homogeneous and of black color. The optical energy gap is E opt g =2.10 eV , and the glass transition temperature is T g =543 K for Ge 25Ga 5Se 70 and T g =633 K for Ge 30Ga 5Se 65. The long-wavelength absorption edge is near 14 μm and it corresponds to multiphonon processes. Doping by Pr 3+ ions creates absorption bands in transmission spectra, which can be assigned to the electron transitions from the ground 3H 4 level to the higher energy levels of Pr 3+ ions 3H 5, 3H 6, 3F 2, 3F 3 and 3F 4, respectively. By excitation with YAG:Nd laser line (1064 nm), two intense luminescence bands (1343 and 1601 nm) were excited. The first band can be ascribed to electron transitions between 1G 4 and 3H 5 energy levels of Pr 3+ ions. Full width at half of maximum (FWHM) of the intensity of luminescence was found to be ∼70 nm for (Ge 25Ga 5Se 70) 1 − x (PrCl 3) x and (Ge 30Ga 5Se 65) 1 − x (PrCl 3) x glasses. The FWHM in selenide glasses is lower than in halide and sulphide glasses. The second luminescence band (1601 nm) can be probably ascribed to the transitions between 3F 3 and 3H 4 energy levels of Pr 3+ ions. The absorption and luminescence spectra of Pr 3+ ions in studied glasses are slightly influenced by stoichiometry of glassy matrix. The Raman spectra of studied glasses were deconvoluted and assignment of Raman bands to individual vibration modes of basic structural units was suggested. The structure of studied glasses is mainly formed by corner-sharing and edge-sharing GeSe 4 tetrahedra. The vibration modes of Ga-containing structural units were not found, they are apparently overlapping with Ge-containing structural units due to small difference between atomic weights of Ge and Ga. In the glasses with substoichiometry of Se, the Ge–Ge bonds of Ge 2Se 6 structural units were found. In Se-rich glasses the Se–Se vibration modes were found. In all studied glasses also `wrong' bonds between like atoms were found in small amounts. Maximum phonon energy of studied glasses is ∼320 cm −1.

Spectroscopic investigations of the 4ƒ5d energy levels of Pr^3+ in fluoride crystals by excited-state absorption and two-step excitation measurements

Excited-state absorption spectra obtained by a pulsed pump–probe technique specially designed for the near-UV spectral domain were recorded in three Pr3+-doped fluoride crystals (KY3F10,LiYF4, and BaY2F8). These excited-state absorption spectra correspond to optical transitions from the 3P0 or the 1D2 metastable levels of the 4f2 configuration up to the first energy levels of the 4f5d electronic configuration. The position, the anisotropic behavior, and the line shape of the observed excited-state absorption bands are discussed and compared with ground-state absorption (from level 3H4) or direct excitation spectra available in the literature. Subsequently, two-step excitation into the 4f5d high-lying energy levels of Pr3 by means of 3P0 and 1D2 is shown to be an efficient way to produce broadband UV fluorescence by use of pump beams in the blue and the near UV.

Spectroscopic investigation of Pr 3+ luminescence in Sr xBa 1− xNb 2O 6 crystal

Energy levels of Pr 3+ in Sr x Ba 1− x Nb 2O 6 (SBN) crystal are determined by absorption spectroscopy. The broad band fluorescence spectrum is identified by exciting Pr 3+ with laser radiation of different wavelengths, and by phase-resolved spectroscopy. The lifetime of the excited state 3P 0 is measured at various temperatures. Calculations of the transition rates of spontaneous radiation and radiationless relaxation demonstrate that the decay of 3P 0 state is dominated by a multiphonon relaxation.

LUMINESCENT PROPERTIES OF Pr3+ IN SBN CRYSTAL

The energy levels of Pr￣(3+) in SBN crystal are determined by means of absorptionspectra and fluorescence spectra. The fluorescence band exhibits a double peak dueto Pr￣(3+) ions at different sites in SBN crystal.This shows that the multiphoton rel-axation of ￣3P_0→￣1D_2 plays a dominant role in the radiationless transition of ￣3P_0 stateof Pr￣(3+) ion by analysing the relation between the fluorescencc lifetime and the sa-mple temperature.

Symmetry, selection rules, and energy levels of Pr 3+:Y 3Al 5O 12

Absorption, fluorescence, and site-selective excitation spectra of Pr 3+: Y 3Al 5O 12 are reported between 0.4 and 6.7 μm at several temperatures between 1.6 and 90 K. The complexity of the spectra indicates that Pr 3+ ions occupy several different sites. The most intense spectra, representing the majority of the Pr 3+ ions in dodecahedral lattice sites, are analyzed on the basis of electric-dipole selection rules for D 2 site symmetry. Weak spectra are reported but not analyzed due to the difficulty in assigning levels to a particular site. Analyses of intense spectra establish the symmetry of 17 Γ 1, 12 Γ 2, 10 Γ 3, and 12 Γ 4 Stark levels. These 51 levels are compared with the results of a crystal-field splitting calculation. A Hamiltonian consisting of Coulombic, spin-orbit, and crystal-field (D 2 symmetry) terms was diagonalized for all manifolds of the Pr 3+ (4f 2) configuration. The rms deviation between calculated and experimental levels is 11 cm −1.

Energy levels of Pr 3+ in the modulated incommensurate structure of ThCl 4

The matrix β-ThCl 4 which presents an incommensurate modulated structure at low temperature is doped with the lanthanide ion Pr 3+. The strong features in the absorption and the laser-excited fluorescence spectra have been interpreted as arising from levels of Pr 3+ in the site of D 2 d symmetry. In a least- squares fit calculation, the best parameters are determined.

Observation of crystal field structure in the conductance of AlAl oxideBi1−xPrx tunnel junctions

Abstract Structure in the conductance of AlAl oxideBi1−xPrx tunnel juctions is compared with the theory of Holzer et al. predicting such structure due to scattering between crystal field split energy levels of the Pr impurity. The experimental results for x = 0.003 and 0.07 are shown to be in excellent agreement with the predictions of Holzer et al., if the crystal field split energy levels of Pr in these BiPr alloys are the same as those measured for bulk BiPr. The structure observed for x = 0.3, while being larger and more complicated than for the more dilute samples, is also shown to be explainable in terms of a modified crystal field split energy level scheme.

Energy Levels of Pr+3 in Pr(NO3)3·6H2O

The energy levels of Pr+3 in Pr(NO3)3·6H2O have been determined from optical absorption experiments on single crystals at 77°K. With the exception of three bands, all of the electronic intra-f1 transitions from the ground state multiplet to higher multiplets were observed. The absorption spectrum along with the determined Stark level schemes of the multiplets and their centers of gravity are reported. An expanded “free-ion” Hamiltonian which includes configuration interactions along with spin–other-orbit and spin–spin interactions was used in the analysis of the multiplet centers of gravity. In a least-squares fit calculation the best-fit free-ion parameters found were F2 = 315.44 cm−1, F4 = 51.17 cm−1, F6 = 5.19 cm−1, ζ4f = 741.12 cm−1, α = 18.76 cm−1, β = −756.77 cm−1, γ = 88.05 cm−1, M0 = 0.43 cm−1. The average deviation between the calculated best fit and the experimental “free-ion” energy levels is 27 cm−1. A first-order perturbation calculation was carried out for the Stark levels of the various observed multiplets of the Pr+3(4f2) ion in a crystal field of C1 symmetry. Because of the large number of crystal field parameters involved in the potential, only a tentative set of best-fit B kq parameters were determined from a least-squares calculation.