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B.m. Angelov - One of the best experts on this subject based on the ideXlab platform.
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Nephelauxetic Effect and spin orbit interaction with pm3 and ho3 ions in crystals
Chemical Physics Letters, 2020Co-Authors: Dimitar Petrov, B.m. AngelovAbstract:Abstract The Nephelauxetic parameters βk = Fk (Ln3+)/Fk (Ln IV) have been determined, with k = 2, 4, 6, Ln3+ – lanthanide ion in crystal, and Ln IV – triply – charged lanthanide free ion. The Slater integrals Fk and the spin – orbit coupling constants ζ4f for Pm IV and Ho IV have been estimated by interpolation from experimental values for other Ln IV. The matrix elements A of spin – orbit interaction have been calculated for the ground levels of both ions, 5I4 and 5I8 respectively. The correlation between βk and the normalized ratios A(Ln3+)/A(Ln IV) in crystals has been considered a combined Nephelauxetic Effect of electrostatic and spin – orbit interactions. Stoichiometric or doped crystals containing Pm3+ or Ho3+ ions include simple and complex halogenides, oxides, oxohalides, phosphates, complex with organic ligand, and hydrates.
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spin orbit coupling and quasi Nephelauxetic Effect in ce3
Physica B-condensed Matter, 2020Co-Authors: Dimitar Petrov, B.m. AngelovAbstract:Abstract A quasi-Nephelauxetic Effect has been found in Ce3+ ions in different crystal matrices by employing spin-orbit interaction for the ground level 2F5/2. The corresponding matrix elements have been determined and normalized relative to the free ion Ce IV- value. These ratios as a function of the crystal field strength Nv exhibit a distinct depression below the free-ion limit. Relationships have been depicted between the number nP of crystal-field parameters employed or the maximum splitting of 2F5/2, on one side, and the crystal field strength, on the other. Examples have been presented with a number of crystals containing Ce3+ ions with different symmetry sites and ligands.
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Spin – orbit coupling and quasi – Nephelauxetic Effect in Ce3+
Physica B: Condensed Matter, 2020Co-Authors: Dimitar N. Petrov, B.m. AngelovAbstract:Abstract A quasi-Nephelauxetic Effect has been found in Ce3+ ions in different crystal matrices by employing spin-orbit interaction for the ground level 2F5/2. The corresponding matrix elements have been determined and normalized relative to the free ion Ce IV- value. These ratios as a function of the crystal field strength Nv exhibit a distinct depression below the free-ion limit. Relationships have been depicted between the number nP of crystal-field parameters employed or the maximum splitting of 2F5/2, on one side, and the crystal field strength, on the other. Examples have been presented with a number of crystals containing Ce3+ ions with different symmetry sites and ligands.
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Nephelauxetic Effect and spin – Orbit interaction with Pm3+ and Ho3+ ions in crystals
Chemical Physics Letters, 2020Co-Authors: Dimitar N. Petrov, B.m. AngelovAbstract:Abstract The Nephelauxetic parameters βk = Fk (Ln3+)/Fk (Ln IV) have been determined, with k = 2, 4, 6, Ln3+ – lanthanide ion in crystal, and Ln IV – triply – charged lanthanide free ion. The Slater integrals Fk and the spin – orbit coupling constants ζ4f for Pm IV and Ho IV have been estimated by interpolation from experimental values for other Ln IV. The matrix elements A of spin – orbit interaction have been calculated for the ground levels of both ions, 5I4 and 5I8 respectively. The correlation between βk and the normalized ratios A(Ln3+)/A(Ln IV) in crystals has been considered a combined Nephelauxetic Effect of electrostatic and spin – orbit interactions. Stoichiometric or doped crystals containing Pm3+ or Ho3+ ions include simple and complex halogenides, oxides, oxohalides, phosphates, complex with organic ligand, and hydrates.
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spin orbit interaction in yb3 ground level and Nephelauxetic Effect in crystals
Chemical Physics, 2019Co-Authors: Dimitar Petrov, B.m. AngelovAbstract:Abstract The matrix elements of spin – orbit interaction (SOI) have been evaluated for the ground level 2F7/2 of Yb3+ ions in crystals. The dependence of the normalized ratios of SOI relative to the free ion Yb IV – value on the crystal field strength Nv has been found similar to the Nephelauxetic Effect. The variations with Nv of the Nephelauxetic parameter β, maximum splitting of the ground level, and the number of crystal – field parameters have been discussed. The analysis comprises 49 symmetry sites of Yb3+ ions in stoichiometric or doped compounds: complexes with inorganic ligands, simple and complex oxides, halogenides, and semiconductors. A discrepancy has been found between theoretical and experimental values of the maximum splitting in the ground level 2F7/2 of Yb3+ ions in crystals.
Dimitar N. Petrov - One of the best experts on this subject based on the ideXlab platform.
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Spin – orbit coupling and quasi – Nephelauxetic Effect in Ce3+
Physica B: Condensed Matter, 2020Co-Authors: Dimitar N. Petrov, B.m. AngelovAbstract:Abstract A quasi-Nephelauxetic Effect has been found in Ce3+ ions in different crystal matrices by employing spin-orbit interaction for the ground level 2F5/2. The corresponding matrix elements have been determined and normalized relative to the free ion Ce IV- value. These ratios as a function of the crystal field strength Nv exhibit a distinct depression below the free-ion limit. Relationships have been depicted between the number nP of crystal-field parameters employed or the maximum splitting of 2F5/2, on one side, and the crystal field strength, on the other. Examples have been presented with a number of crystals containing Ce3+ ions with different symmetry sites and ligands.
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Nephelauxetic Effect and spin – Orbit interaction with Pm3+ and Ho3+ ions in crystals
Chemical Physics Letters, 2020Co-Authors: Dimitar N. Petrov, B.m. AngelovAbstract:Abstract The Nephelauxetic parameters βk = Fk (Ln3+)/Fk (Ln IV) have been determined, with k = 2, 4, 6, Ln3+ – lanthanide ion in crystal, and Ln IV – triply – charged lanthanide free ion. The Slater integrals Fk and the spin – orbit coupling constants ζ4f for Pm IV and Ho IV have been estimated by interpolation from experimental values for other Ln IV. The matrix elements A of spin – orbit interaction have been calculated for the ground levels of both ions, 5I4 and 5I8 respectively. The correlation between βk and the normalized ratios A(Ln3+)/A(Ln IV) in crystals has been considered a combined Nephelauxetic Effect of electrostatic and spin – orbit interactions. Stoichiometric or doped crystals containing Pm3+ or Ho3+ ions include simple and complex halogenides, oxides, oxohalides, phosphates, complex with organic ligand, and hydrates.
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Spin – Orbit interaction in Yb3+ – Ground level and Nephelauxetic Effect in crystals
Chemical Physics, 2019Co-Authors: Dimitar N. Petrov, B.m. AngelovAbstract:Abstract The matrix elements of spin – orbit interaction (SOI) have been evaluated for the ground level 2F7/2 of Yb3+ ions in crystals. The dependence of the normalized ratios of SOI relative to the free ion Yb IV – value on the crystal field strength Nv has been found similar to the Nephelauxetic Effect. The variations with Nv of the Nephelauxetic parameter β, maximum splitting of the ground level, and the number of crystal – field parameters have been discussed. The analysis comprises 49 symmetry sites of Yb3+ ions in stoichiometric or doped compounds: complexes with inorganic ligands, simple and complex oxides, halogenides, and semiconductors. A discrepancy has been found between theoretical and experimental values of the maximum splitting in the ground level 2F7/2 of Yb3+ ions in crystals.
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Nephelauxetic Effect and 〈rk〉4f radial integrals of Tm3+ in crystals
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2015Co-Authors: Dimitar N. PetrovAbstract:Abstract Bonding and covalency parameters have been evaluated from the Nephelauxetic ratios β k = F k (crystal)/ F k (free ion), with k = 2, 4, 6, for 24 halide and chalcogenide crystals containing Tm 3+ ions. The radial expectation values for 4 f electrons 〈 r k 〉 4 f of Tm 3+ ion in certain complex oxides, fluorides, and a sulfide have been determined by means of experimental Slater parameter shifts Δ F k relative to the F k values for the free ion Tm IV. The 〈 r k 〉 1 f values derived in the dielectric screening model have been compared with those computed by different types of 4f wave functions as well as with other estimates.
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Radial integrals 〈rk〉4f and Nephelauxetic Effect of Nd3+ in crystals
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2013Co-Authors: Dimitar N. Petrov, B. AngelovAbstract:Abstract The radial expectation values 〈 r k 〉 4 f , k = 2, 4, 6, for oxygen- or halogen- coordinated Nd3+ ions in 25 crystals have been obtained from experimental Slater parameter shifts ΔFk = Fk (free ion) – Fk (crystal) by means of the dielectric screening model. The 〈 r k 〉 4 f values found by this new approach are compatible with those computed by relativistic 4f wave functions. The Nephelauxetic ratios βk in respect to the free ion Nd IV have been also determined and related to covalency and bonding parameters.
Dimitar Petrov - One of the best experts on this subject based on the ideXlab platform.
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Nephelauxetic Effect and spin orbit interaction with pm3 and ho3 ions in crystals
Chemical Physics Letters, 2020Co-Authors: Dimitar Petrov, B.m. AngelovAbstract:Abstract The Nephelauxetic parameters βk = Fk (Ln3+)/Fk (Ln IV) have been determined, with k = 2, 4, 6, Ln3+ – lanthanide ion in crystal, and Ln IV – triply – charged lanthanide free ion. The Slater integrals Fk and the spin – orbit coupling constants ζ4f for Pm IV and Ho IV have been estimated by interpolation from experimental values for other Ln IV. The matrix elements A of spin – orbit interaction have been calculated for the ground levels of both ions, 5I4 and 5I8 respectively. The correlation between βk and the normalized ratios A(Ln3+)/A(Ln IV) in crystals has been considered a combined Nephelauxetic Effect of electrostatic and spin – orbit interactions. Stoichiometric or doped crystals containing Pm3+ or Ho3+ ions include simple and complex halogenides, oxides, oxohalides, phosphates, complex with organic ligand, and hydrates.
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spin orbit coupling and quasi Nephelauxetic Effect in ce3
Physica B-condensed Matter, 2020Co-Authors: Dimitar Petrov, B.m. AngelovAbstract:Abstract A quasi-Nephelauxetic Effect has been found in Ce3+ ions in different crystal matrices by employing spin-orbit interaction for the ground level 2F5/2. The corresponding matrix elements have been determined and normalized relative to the free ion Ce IV- value. These ratios as a function of the crystal field strength Nv exhibit a distinct depression below the free-ion limit. Relationships have been depicted between the number nP of crystal-field parameters employed or the maximum splitting of 2F5/2, on one side, and the crystal field strength, on the other. Examples have been presented with a number of crystals containing Ce3+ ions with different symmetry sites and ligands.
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spin orbit interaction in yb3 ground level and Nephelauxetic Effect in crystals
Chemical Physics, 2019Co-Authors: Dimitar Petrov, B.m. AngelovAbstract:Abstract The matrix elements of spin – orbit interaction (SOI) have been evaluated for the ground level 2F7/2 of Yb3+ ions in crystals. The dependence of the normalized ratios of SOI relative to the free ion Yb IV – value on the crystal field strength Nv has been found similar to the Nephelauxetic Effect. The variations with Nv of the Nephelauxetic parameter β, maximum splitting of the ground level, and the number of crystal – field parameters have been discussed. The analysis comprises 49 symmetry sites of Yb3+ ions in stoichiometric or doped compounds: complexes with inorganic ligands, simple and complex oxides, halogenides, and semiconductors. A discrepancy has been found between theoretical and experimental values of the maximum splitting in the ground level 2F7/2 of Yb3+ ions in crystals.
Peter Nelson - One of the best experts on this subject based on the ideXlab platform.
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LIGAND FIELD STABILIZATION ENERGIES OF THE HEXAAQUA 3+ COMPLEXES OF THE FIRST TRANSITION SERIES
Inorganic Chemistry, 1999Co-Authors: David A. Johnson, Peter NelsonAbstract:An analysis of the ligand field stabilization energy which makes allowance for the Nephelauxetic Effect is shown to give satisfactory results when applied to the hydration enthalpies of the hexaaqua 3+ complexes of the first transition series. The contribution from the Nephelauxetic Effect is substantial, and the baseline for zero ligand field stabilization energy is displaced below the d0 point. In these respects, the complexes show a closer resemblance to the hexafluorometalates(III) than to the hexaaqua 2+ ions. In the course of the analysis, the electronic spectra of the cesium alums of vanadium(III), manganese(III), and cobalt(III) are reexamined, and thermodynamic properties of particular complexes are calculated. These include Δ (Ti3+,aq), E⊖(Ti3+|Ti2+), and the relative stabilities of the high- and low-spin states of Co3+(aq), Mn3+(aq), and Cr2+(aq). The general influence of ligand field stabilization energies on redox potentials is also discussed.
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Ligand-field stabilization energies of the first-row transition-metal dihalides and their bearing on the Irving–Williams rule
Journal of The Chemical Society-dalton Transactions, 1995Co-Authors: David A. Johnson, Peter NelsonAbstract:A new analysis of the ligand-field stabilization energy which allows for contributions from the Nephelauxetic Effect, is shown to give satisfactory results for solid dihalides of the first transition series. In agreement with the Nephelauxetic series, this contribution increases with the size of the halide ligand, and sometimes exceeds 50% in the diiodides. The new treatment seems to be an improvement upon those which equate ligand-field and d-orbital stabilization energies; it suggests that the value of ΔfH⊖(VI2, s) recommended by the National Bureau of Standards is 30–40 kJ mol–1 too negative. The formation of a solid dihalide from aqueous solution is used as a model for formation of an aqueous octahedral halogeno complex. It seems that the weak Nephelauxetic Effect of water as a ligand contributes to the emergence of the Irving–Williams order of stability in complexing and pseudo-complexing reactions for the oxidation states MnII→ZnII in aqueous solution.
Andrzej Suchocki - One of the best experts on this subject based on the ideXlab platform.
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Nephelauxetic Effect in high-pressure luminescence of transition-metal ion dopants
Journal of Luminescence, 2006Co-Authors: Andrzej Suchocki, S. W. Biernacki, Marek GrinbergAbstract:Application of the model of the Nephelauxetic Effect based on Harrison theory of bonding to various transition-metal dopants is reviewed. This one-parameter model describes pressure dependence of the Nephelauxetic Effect in various compounds with a very good accuracy. Additional studies are necessary to reveal the dependence of fitting parameter on the properties of more complicated many-element compounds.
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Nephelauxetic Effect in luminescence of Cr3+-doped lithium niobate and garnets
Journal of Luminescence, 2003Co-Authors: Andrzej Suchocki, S. W. Biernacki, Agata Kaminska, Luis ArizmendiAbstract:Abstract The model based on Harrison theory of bonding is used to explain quantitatively the Nephelauxetic Effect in LiNbO 3 and Y 3 Al 5 O 12 crystals doped with chromium, studied by high-hydrostatic pressure spectroscopy. The model uses only one adjustable parameter and can also be used for other dopant–ligands systems in different compounds. We show that not only ligands, but also the second neighbors of the dopant, influence the Nephelauxetic Effect.
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Nephelauxetic Effect in LiNbO3:Cr3+ crystals
Applied Physics Letters, 2002Co-Authors: S. W. Biernacki, Andrzej Suchocki, Agnieszka Kamińska, Luis ArizmendiAbstract:A model, based on the Harrison theory of bonding is developed for quantitative explanation of the Nephelauxetic Effect, i.e., a reduction of interelectronic crystal field Racah repulsion parameters B and C due to the covalency of bonds. The results are used for a description of the Effect in chromium-doped lithium niobate crystals. The model can be also applied to other systems.