Analysis of the optical spectrum of Ho3+ in LiYF4

The energy levels for Ho³⁺ in single crystal LiYF₄ from 0–21,300 cm^?1 have been determined from polarized absorption and fluorescence spectra using crystals at temperatures between 4 and 300°K. Energy level assignments were made initially by comparing the crystal spectra with energy levels calculated by using crystal field parameters interpolated from previously reported analyses of Nd³⁺, Er³⁺ and Tm³⁺ in LiYF₄. The energy level scheme identifies energy levels in the 10 lowest J-multiplets and gives calculated energies for the next six higher J-multiplets. The crystal field parameters were varied to obtain a best fit between experimental and theoretical energies, and the final values B₂₀ = 410, B₄₀ = ? 615, B₄₄ = 819, B₆₀ = ? 27.9 and B₆₄ = 677 ± i32.8 cm^?1 give an r.m.s. fit of 2.78 cm^?1. The calculations were made by diagonalizing the crystal field Hamiltonian, H_x = Σ_kmB_kmC_km, in the space of ten lowest J-multiplets spanned by intermediate coupled free-ion wavefunctions calculated using the free-ion parameters of Carnall et al. for Ho in aqueous solution. The calculated g_∥ for the Γ_3.4 ground state of 13.63 compares favorably with a previously reported value of 13.3 ± 0.1.     

Magnetic and ESR studies of Er3+ in lanthanum dihydride LaH2

Er³⁺ electron spin resonance ESR and magnetic susceptibility have been studied in metallic lanthanum dihydride host. The ESR spectrum contains a single asymmetrical line with g-factor g = 6.68 ± 0.05 close to that expected for Γ₇ as ground state. The experimental magnetic susceptibility was interpreted on the base of LLW cubic crystal field Hamiltonian. The best fit of the experimental data has been obtained for the following B₄ and B₆ crystal field parameters: B₄ = ?5.2 × 10^?3 K; B₆ = 3.8 × 10^?5 K which support the anionic-like character hydridic model of hydrogen atoms in this hydride.     

EPR of Mn2+ doping unannealed single crystal of (La2O3)0.95(CeO2)0.05

X-band room temperature EPR spectra have been recorded for Mn²⁺ ion doping unannealed (La₂O₃)_0.95(CeO₂)_0.05 host crystal. The data are analysed using a rigorous least-squares fitting procedure in which a large number of lines characterized by ΔM = ± 1, Δm = 0 transition, obtained for several orientations of the static magnetic field, are simultaneously fitted. Combined with the knowledge of the absolute sign of the hyperfine interaction parameter. A, the hyperfine Hamiltonian parameters A, B, Q as reported in this paper, are given with their correct signs. The information on the linewidth is used to deduce the deviation of the crystal-field axes of different Mn²⁺ ions from the c axis; on the basis of the model proposed here these deviations are found to be between 0 and 10°.     

Emission and excitation spectra of Bi2Ge3O9:Eu3+

The emission and excitation spectra of the Bi₂Ge₃O₉:Eu crystal are observed at 77 K and 297 K. The spectra contain groups of sharp lines which are attributed to the transitions within 4f⁶ (Eu³⁺) configuration. The numbers of Stark splitting of terminal levels of transitions from ⁵D₀ and ⁷F₀ multiplets indicate that Eu³⁺ substitutes for Bi³⁺ in Bi₂Ge₃O₉. Tentative assignment of Stark levels of ⁷F_0-4 multiplets is made to crystal quantum numbers of C₃ symmetry which represents the site symmetry of Bi³⁺ in Bi₂Ge₃O₉. The following set of values of crystal field parameters of the C₃ point group is found to give the best overall agreement between the observed energy levels and the calculated levels: B²₀ = -533.84 cm^-1, B⁴₀ = 1085.99 cm^-1, Re(B⁴₃) = 327.57 cm^-1, Im(B⁴₃) = 75.209 cm^-1, B⁶₀ = 185.02 cm^-1, Re(B⁶₃) = - 68.475 cm^-1, Im(B⁶₃) = - 300.45 cm^-1, Re(B⁶₆) = 137.24 cm^-1 and Im(B⁶₆) = 882.29 cm^-1.     

EPR of orthorhombic Gd3+-M+ complexes in SrF2

In this paper we report new results of EPR experiments on orthorhombic Gd³⁺-M⁺ complexes (M = Na, K, Rb and Ag) in SrF₂. Special attention is payed to the second degree crystal field parameters B⁰₂ and B²₂ and a comparison with earlier results on corresponding complexes in CaF₂ and BaF₂ is made. We conclude that the main contributions to these crystal field parameters are of electrostatic nature.     

Optical absorption spectrum of Cr3+ ion doped in zinc cesium sulphate hexahydrate

Optical absorption spectrum of Cr³⁺ ion doped in zinc cesium sulphate hexahydrate single crystal has been studied both at room and liquid nitrogen temperatures. From the nature and position of the bands a successful interpretation of all the bands could be made assuming octahedral symmetry for the Cr³⁺ ion in the crystal. The observed bands are assigned to the transitions from the ground ⁴A_2g(F) state to the excited ²E_g(G), ²T_1g(G), ⁴T_2g(F) and ⁴T_1g(F) states.The crystal field parameters Dq = 1735 cm^?1, B = 635 cm^?1 and C = 4.75 B are found to give a good fit to the observed band positions.     

Franck-Condon factors and absolute transition probabilities for the if (B3Π0+-X1Σ+) transition

Improved spectroscopic constants have been used to calculate Rydberg-Klein-Rees (RKR) potentials and Franck-Condon factors for the IF(B³Π₀₊-X¹Σ⁺) transition. The Franck-Condon factors are generally in good agreement with previously calculated values, but differ by as much as 30% for transitions from higher levels of the B-state. Several experimentally measured relative transition moment functions have been evaluated and the best scaled, so that the total transition probability calculated for each B-state vibrational level, A(v'), matched measured values. The scaled function was then used to calculate individual transition probabilities, A(v',v), for the vibronic transitions.     

Crystal field splitting of Pr3+ in PrAl2 investigated by inelastic neutron scattering

We report the.results of an experimental determination of the crystal field splitting of Pr³⁺ in PrAl₂ by means of inelastic neutron scattering. For the crystal field parameters we obtain B₄ = (47.2 ± 4.0) × 10^?4 meV and B₆ = ? (156 ± 12) × 10^?6 meV.     

Spectroscopy of multisites Cr3+ and Nd3+ in yttrium aluminium garnet

Cr³⁺ and Nd³⁺ non-equivalent crystal field sites were observed. By use of a high-resolution dye laser,²E and⁴A₂ splittings, zero-phonon⁴A₂ ²E,²T₁,⁴T₂ transitions and vibronic levels of²E doublets of Cr³⁺ non-equivalent centres were recorded. Energy transfers from Cr³⁺ multisites to Nd³⁺ were studied by site-selective spectroscopy and fluorescence decays.     

Cr3+掺杂的Cd3Al2Ge3O12光谱特性及晶场参数计算

采用高温固相法合成了Cd₃Al₂Ge₃O₁₂：Cr³⁺多晶材料,利用X射线衍射对其结构进行了分析,通过Cr³⁺的室温吸收光谱、室温和77K发射光谱分别对其光谱特性和晶场参数进行了分析和计算.结果表明：在450 nm的蓝光激发下,Cd₃Al₂Ge₃O₁₂：Cr³⁺室温发 关键词： 3Al₂Ge₃O₁₂：Cr³⁺')" href="#">Cd₃Al₂Ge₃O₁₂：Cr³⁺ 荧光光谱 晶场参数 可调谐激光     

Electron-nuclear double resonance of cubic 55Mn2+ in GaP

ENDOR measurements were used to determine the cubic crystal field splitting parameter a, and the nuclear spin-Hamiltonian parameters A, g_Nβ_N and U of the cubic ⁵⁵Mn²⁺ centre in GaP at 4.2K.     

A powder neutron diffraction study of the ErCu2Ge2 compound - crystal field

The compound ErCu₂Ge₂ was studied by neutron diffraction. The diffraction diagram of this compound at 170 K agrees with its crystallographic structure. Its diagram at 1.9 K reveals the existence of superlattice lines consistent with a cell doubled in the a and c directions. The erbium magnetic moment (8.0±0.4)μ_B lies on the c-axis. Crystal field calculations on the Er³⁺ site give 7.9μ_B, with easy magnetization axis the c-axis of the crystal. Copper must contribute to the V^m_l crystal field parameters with a charge equal to 0.6⁺.     

Energy levels calculation for Er3+: LiYF4

The complete configuration 4f¹¹ of Er³⁺ was diagonalized with a Hamiltonian containing electrostatic, two-body and three-body configuration interaction, spin-orbit and crystal field parameters of LiYP₄. A set of 18 parameters was adjusted to fit the experimental energy levels as given by Petrov and Tkachuk.     

Absorption spectrum of VO2+ in zinc cesium sulphate hexahydrate

Results of optical absorption spectra of VO²⁺ ion doped in zinc cesium sulphate hexahydrate are reported. The observed bands have been assigned transitions from the ground ²B_2g state to the excited ²E_g, ²B_ig and ²A_1g states. From the nature and position of the bands a successful interpretation of all observed bands could be made. The crystal field and molecular orbital coefficients are reported.     

Crystal field splitting of 5d states in Ce3+:YPO4

The superposition model is used to obtain a new identification of the 5d levels in Ce³⁺: YPO₄, resulting in a revised parametrization of the 5d crystal field. Electrostatic and pseudo-potential models are employed to relate these parameters to those obtained from 4f crystal field splittings.     

Absorption spectrum of Cr3+ ion doped in lithium ammonium sulphate single crystal

The absorption spectrum of Cr³⁺ ion doped in lithium ammonium sulphate single crystal has been studied both at room (300 K) and liquid nitrogen (77 K) temperatures. From the nature and position of the observed bands, O_h symmetry is assumed for the ion. The spectroscopic parameters derived for the ion in the crystal at 77 K are Dq = 1655 cm^?1, B = 735 cm^?1 and C/B = 4.4     

High-resolution Fourier spectrometry of 14N2 infrared emission spectrum: Extensive analysis of the B3Πg-A3Σu+ system

The B³Π_g-A³Σ_u⁺ system of N₂ excited in a microwave discharge was recorded between 3 000 and 18 000 cm^?1 with a high-resolution Fourier spectrometer. There are no observed irregularities in the levels of the A³Σ_u⁺ and B³Π_g states at least for the values of v and J considered here, except the predissociation in the B³Π_g state for v = 12 and J higher than 33. This predissociation will be checked with more complete data in another article. Thirty three bands of the first positive system with 0 ≤ v′ ≤ 12 and 0 ≤ v″ ≤ 8 are analyzed. The molecular parameters of the B³Π_g and A³Σ_u⁺ are obtained by a complete fitting procedure. Derived values of equilibrium constants are deduced; RKR potential energy curves for the two states are constructed, and the Franck-Condon factors calculated for the A-B system.     

Racah and Judd-Ofelt parameters for Pr3+, Nd3+, and Er3+ ions in a laser liquid

The values of the Slater-Condon (F₂, F₄, F₆), Racah (E¹, E², E³) and Lande ξ₄f coefficients the nephelauxetic ratio (β), the bonding parameter (σ), and the Judd-Ofelt intensity (T_λ) parameters have been calculated from the reported absorption spectra of Pr³⁺, Nd³⁺, and Er³⁺ ions in an aprotic solvent SeOCl₂ acidified with antimony pentachloride. The nature of the bonding is suggested to be covalent for praseodymium, neodymium and erbium ions in the laser liquid in view of the magnitude of the respective bonding parameters.     

Cr3+−Cr3+ excited state Raman scattering from molecular vibrations in binuclear Cs3Cr2Cl9 induced by exchange striction

On increasing the temperature, several new bands appear at higher energy from their parent vibrational modes in the Raman spectrum of the molecular complex Cr₂Cl^3?₉. The parent and new bands have intensities that follow the thermal population factors of various ⁴A_2g⁴A_2g Cr³⁺ pair states. This behaviour is attributed to exchange striction which produces a change in vibrational energy with excited state for those normal modes with large net axial Cr³⁺?Cr³⁺ displacements.     

BeAl2O4:Cr3+的晶场能级

金绿宝石中镜对称格位上Cr³⁺(Ⅱ)离子的⁴T₂,⁴T₁和²E能级与该材料的激光运转有关。⁴T₂和⁴T₁能级各分裂成三个子能级。为从偏振吸收谱上确定BeAl₂O₄:Cr³⁺的能级图,本文计算了⁴T₂和⁴T₁的分裂,找到了对谱方法,得到了表征能级分裂的参量K_{1和K2的值。最后给出了以低点群不可约表示标号的、BeAl2O4:Cr³⁺(Ⅱ)的晶场能级图。 关键词：}