Trivalent Praseodymium Research Articles

Sensitizing Pr3+ ions by Tm3+ ions in phosphate glass

Energy transfer from trivalent thulium to trivalent praseodymium in sodium phosphate glass has been observed. The transfer occurs by ion pair relaxation between Tm and Pr. High transfer efficiencies have been observed for donor-acceptor distances lying between 16.8 and 20.2 A.

Thermal and spectral studies of some rare earth chelates of chlorojuglone antibacterials

The metal chelates of juglone, 3-chlorojuglone and 2,3-dichlorqjuglone with trivalent lanthanum, cerium and praseodymium have been synthesised. The thermal, spectral and magnetic properties of these chelates were investigated to study the effect of substitution on the chelating ability of the ligand.

Two-pulse and stimulated nuclear-quadrupole-resonance echoes in YAlO3:Pr3+

The dephasing of trivalent praseodymium dilute in yttrium aluminum oxide (${\mathrm{YAlO}}_{3}$) in the ground electronic state $^{3}$${\mathit{H}}_{4}$ state is evaluated using an optically detected method, to measure two-rf-pulse- and three-rf-pulse-stimulated nuclear quadrupole echoes. The magnitude of the echo is obtained by detecting the weak Raman optical field generated by the interaction of the magnetic moment of the echo and a light beam resonant with the $^{3}$${\mathit{H}}_{4}$(0 ${\mathrm{cm}}^{1}$) to $^{1}$${\mathit{D}}_{2}$(16 374 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$) optical transition. This same light beam is used as an optical pump (37-ms duration) prior the rf-pulse sequence to increase the population difference of the hyperfine energy levels, thereby improving the echo signal. The light is turned off 9 ms before the rf-pulse sequence and remains off until the echo to avoid optical-pumping effects on the measured nuclear-quadrupole-resonance (NQR) echo lifetime. The dephasing time ${\mathit{T}}_{2}$ from two-pulse nuclear-quadrupole-echo measurement is found to be 366\ifmmode\pm\else\textpm\fi{}29 \ensuremath{\mu}s.Three-pulse-stimulated echoes show a fast decay at short times, followed by a slower (240 ms) decay. The Hu-Hartmann uncorrelated-sudden-jump model was fitted to the data. For the two-pulse echo, the best approximation to the data is obtained using a fluctuating field amplitude \ensuremath{\Delta}${\mathrm{\ensuremath{\omega}}}_{1/2}$=7000 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$, and the fluctuation rate W=2100 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. In contrast to this, the three-pulse echo data, measured with a much smaller separation of the first two pulses \ensuremath{\tau}, shows an approximate fit using \ensuremath{\Delta}${\mathrm{\ensuremath{\omega}}}_{1/2}$\ensuremath{\approxeq}60 000 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ (\ensuremath{\tau}40 \ensuremath{\mu}s) and W=12 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ for data plotted versus the separation between the second and third rf pulses T for several values of the separation of the first two pulses \ensuremath{\tau}, and \ensuremath{\Delta}${\mathrm{\ensuremath{\omega}}}_{1/2}$=125 000 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ and W=20 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ for data at three fixed values of T, plotted versus \ensuremath{\tau}. The apparent discrepancy between the two-pulse and the three-pulse fits is attributed to two different dephasing host Al nuclei. The fluctuating fields due to bulk Al are effective in dephasing the Pr moment for \ensuremath{\tau}\ensuremath{\ge}${\mathit{T}}_{2}$, and the frozen-core Al, which surround the ${\mathrm{Pr}}^{3+}$ ion, produce a much larger effective field that fluctuates much more slowly, are the dephasing agent for \ensuremath{\tau}\ensuremath{\ll}${\mathit{T}}_{2}$.

Energy transfer from Mn 2+ to Pr 3+ in phosphate glass

Energy transfer from optically excited divalent manganese to trivalent praseodymium in phosphate glass has been observed. Large values of transfer efficiencies and transfer probabilities suggest that Mn 2+ can be a good sensitizer for Pr 3+ in phosphate glass. The energy transfer mechanism is found to be mainly electric dipole-dipole in nature.

Magnetocrystalline anisotropy of the Pr 2Fe 14B compound

The properties of the trivalent praseodymium ion in the Pr 2Fe 14B compound have been analyzed within a single-ion Hamiltonian. Values for the macro- and micro-scopic parameters of the praseodynium anisotropy at 4.2 K have been derived from magnetization experiments.

Spectrophotometric determination of some lanthanides using 3-hydroxy-2-naphthoic acid azo dyes

A comparative spectrophotometric study of the reaction of some substituted phenylazo-3-hydroxy-2-naphthoic acid derivatives with trivalent yttrium, lanthanum, praseodymium, neodymium, samarium, gadolinium, and erbium ions has shown that 1:1 and 1:2 complexes are formed at pH 7–8. Applications of these chelating agents for direct spectrophotometric determination of the lanthanons under investigation and also as indicators for spectrophotometric titration with EDTA were reported. Interference of various cations and anions in this method was also studied. Beer's law was obeyed for metal ions of up to 5–10 ppm.

An explanation of the 1D2 anomalous crystal field splitting in PrCl3

Taking into account configuration interaction between 4f2 and 4f15d1 via the odd rank crystal field parameters eliminates most of the well-known discrepancy of the 1D2 multiplet of trivalent praseodymium in PrCl3, found when ‘‘standard’’ crystal field treatment is applied to experimental data. Ab initio values of crystal field parameters agree with the new parameters including the configuration interaction.

Optically detected multipulse nuclear-quadrupole-resonance studies of trivalent praseodymium in zero and weak static magnetic fields.

Optically detected multipulse nuclear quadrupole resonance is used to study trivalent praseodymium in lanthanum trifluoride in zero and weak static magnetic fields. A spin-locking spin-echo rf pulse sequence consisting of a \ensuremath{\pi}/2 preparation pulse, followed by repeated sequence of space t, a \ensuremath{\pi}/2 pulse phase shifted by 90\ifmmode^\circ\else\textdegree\fi{} from the preparation pulse, and a space t. A Raman heterodyne scheme was used for optical detection. The coherence was observed to decay exponentially at a rate of 51 \ensuremath{\mu}sec (6.2 kHz) in zero static magnetic field. For static magnetic fields of 80 G applied along the ${c}_{3}$ axis the decay was described by time constants of 76 \ensuremath{\mu}sec (4.2 kHz) and 372 \ensuremath{\mu}sec (855 Hz). This represents a lengthening of the coherence time from a previously reported (two-pulse spin echo) 16.9 \ensuremath{\mu}sec (18.8 kHz) at zero field and a measured 37.5 \ensuremath{\mu}sec (8.5 kHz) at 80 G.

Thermogravimetric, potentiometric, conductimetric and spectrometric studies on lanthanide complexes with some hydroxynaphthoic acid AZO dyes

Potentiometric, conductimetric, IR, NMR and TGA studies have been carried out on the complexes of trivalent yttrium, lanthanum, praseodymium, neodymium, samarium, gadolinium and erbium with some azo derivatives of 3-hydroxy-2-naphthoic acid. The ionization constants of the reagents and the formation constants of their metal complexes have been determined potentiometrically by Sarin's method. Complexation has also been studied by a conductimetric titration method and the solid complexes formed were separated, analysed and their structures have been elucidated by IR, NMR and TGA studies.

Pr2Br5: No mixed valence praseodymium bromide

AbstractThe metallothermic reduction of praseodymium tribromide, PrBr3, with lithium metal (molar ratio 1:1) in sealed tantalum containers at 850°C yields bronze lustrous rods of Pr2Br5. The crystal structure (monoclinic, P21/m, Z = 2, a = 774.38(4), b = 415.33(3), c = 1327.06(9) pm, β = 90.816(6)°, Vm = 128.52(2) cm3 mol−1) contains seven‐ and eight‐coordinate trivalent praseodymium in mono‐ and bicapped trigonal prisms. Pr2Br5 should therefore be formulated as (Pr3+)2(Br−)5(e−). It is isostructural with Pr2I5 and is believed to be identical with PrBr2,38 reported for the Pr/PrBr3 system.

Application of 8-hydroxyquinoline-5-sulfonic acid in the spectrophotometric determination of some lanthanides

A simple, sensitive, and selective spectrophotometric method for the determination of trivalent praseodymium, neodymium, samarium, gadolinium, dysprosium, and erbium ions with 8-hydroxyquinoline-5-sulfonic acid is described. The optimum conditions for determination of down to 10.0 μg/ml of lanthanide ion are reported. The proposed method shows an average recovery of 99.9% with standard deviation not exceeding 0.1%. The metal-ligand ratio and stability constant of the chelates are determined.

Nuclear-quadrupole-resonance study of the ground state of praseodymium in lanthanum trifluoride

A nuclear-quadrupole-resonance study of trivalent praseodymium in a lanthanum trifluoride single crystal is presented. The magnitudes and orientation of the enhanced nuclear Zeeman tensor are obtained for the six magnetically inequivalent sites from measurements in 100-G magnetic fields. By comparing the directions of the site $y$ axis and the crystal $a$ axis, it is concluded that the ${\mathrm{Pr}}^{3+}$ site symmetry is ${C}_{2}$ and not ${C}_{s}$. From a study of the polarization of the optical pump transition for each ${\mathrm{Pr}}^{3+}$ site, it is determined that the $^{3}H_{4} (0 {\mathrm{cm}}^{\ensuremath{-}1})\ensuremath{-}^{1}D_{2} (16872 {\mathrm{cm}}^{\ensuremath{-}1})$ optical transition is an electric dipole transition.

Stability Constants and Thermodynamic Parameters of Trivalent Praseodymium and Neodymium Complexes with Glutamic acid : A Polarographic Study

Stability Constants and Thermodynamic Parameters of Trivalent Praseodymium and Neodymium Complexes with Glutamic acid : A Polarographic Study

Addendum to "Hyperfine interaction in the lowest levels of theH43andD21states of trivalent praseodymium in yttrium aluminum perovskite (Y AIO3)"

The magnetic hyperfine tensor of ${\mathrm{Pr}}^{3+}$ in single-crystal Y Al${\mathrm{O}}_{3}$ has been measured in the ground electronic state through a study of the ${I}_{z}=\frac{1}{2}\ensuremath{-}{I}_{z}=\frac{3}{2}$ NMR transitions in a low static magnetic field. The directions of the $x$, $y$, and $z$ axes of the two ${\mathrm{Pr}}^{3+}$ sites are determined. The magnetic splitting factors are ${\ensuremath{\gamma}}_{z}=11.648\ifmmode\pm\else\textpm\fi{}0.053$, ${\ensuremath{\gamma}}_{x}=3.881\ifmmode\pm\else\textpm\fi{}0.036$, and ${\ensuremath{\gamma}}_{y}=2.50\ifmmode\pm\else\textpm\fi{}0.1$ kHz/G. The pseudoquadrupole interaction from the second-order magnetic hyperfine interaction is found to account for 94% of the observed zero-field splittings.

Hyperfine interaction in the lowest levels of theH43andD21states of trivalent praseodymium in yttrium aluminum perovskite (YAlO3)

The hyperfine interaction in the lowest levels of the $^{3}H_{4}$ and $^{1}D_{2}$ states of praseodymium in yttrium aluminum perovskite has been measured. The ground-state ($^{3}H_{4}$) measurements were made using a rf optical technique. The excited-state ($^{1}D_{2}$) measurements were made using an enhanced and saturated absorption method. The energy-level separations, spin-Hamiltonian parameters, ground-state magnetic splitting factor and orientation, and the ground-state linewidths are reported. The crystal-field splittings of the $^{3}H_{4}$ and $^{1}D_{2}$ manifolds were measured.

Mixed crystal phases in the system CeO 2-PrO x

Ceria and praseodymia form homogeneous crystalline phases when mixed or coprecipitated and heated to 1000 °C. Several series of such phases with various Ce:Pr ratios were equilibrated at 400 °C under various pressures of oxygen. From the chemical and X-ray analyses of these mixed oxide samples it can be concluded that the presence of cerium dioxide favours the formation of tetravalent rather than trivalent praseodymium.

Stability Constants and Thermodynamic Functions of Trivalent Lanthanum, Cerium, Praseodymium, Neodymium and Samarium Complexes with 2-(p-sulphophenylazo) 1, 8-Dihydroxy naphthalene 3, 6-Disulphonic Acid (Trisodium salt) [SPADNS

Stability Constants and Thermodynamic Functions of Trivalent Lanthanum, Cerium, Praseodymium, Neodymium and Samarium Complexes with 2-(p-sulphophenylazo) 1, 8-Dihydroxy naphthalene 3, 6-Disulphonic Acid (Trisodium salt) [SPADNS

Stepwise Stability Constants of Trivalent Scandium, Yttrium, Lanthanum, Cerium, Praseodymium and Neodymium Complexes with Ammonium Aurintricarboxylate : A Potentiometric Study

Stepwise Stability Constants of Trivalent Scandium, Yttrium, Lanthanum, Cerium, Praseodymium and Neodymium Complexes with Ammonium Aurintricarboxylate : A Potentiometric Study

Fluorescence line narrowing of trivalent praseodymium in lanthanum trifluoride - the resonant transitions

The fluorescence line narrowing technique is used to study homogenous linewidths of several resonant transitions ( 1D 2 ↔ 3H 4) for the first time. At temperatures exceeding 10 K the linewidths can be fitted by the theory of phonon-induced relaxation. However the narrowest linewidth (10 MHz at 4.5 K) is 16× larger than the width predicted by the theory.

Fluorescence line narrowing of trivalent praseodymium in lanthanum trifluoride single crystal—Phonon-induced relaxation

Fluorescence line narrowing of trivalent praseodymium in lanthanum trifluoride single crystal—Phonon-induced relaxation