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T. P. Sinha - One of the best experts on this subject based on the ideXlab platform.
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MÖSSBAUER Quadrupole Splitting of Fe2+ in NH4CoCl3 UNDER ORBIT–LATTICE INTERACTION
International Journal of Modern Physics B, 2001Co-Authors: T. P. SinhaAbstract:The effect of orbit–lattice interaction (vibronic coupling) has been considered to explain the observed temperature dependence of Mossbauer Quadrupole Splitting of Fe2+ ions in NH4CoCl3 over 27 to 250 K. The orbit–lattice interaction accounts for the thermal modulation of the electronic charge distribution of Fe2+ due to vibration of the surrounding ligands. The various lattice dynamical parameters are estimated and then Quadrupole Splitting is explicitly calculated as a function of temperature. One obtains a reasonably good agreement with the experimental data which shows that the vibronic coupling is quite realistic and important.
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Vibronic coupling effect on Fe2+ Mössbauer Quadrupole Splitting in CsCoCl3
Journal of Physics: Condensed Matter, 2001Co-Authors: T. P. SinhaAbstract:The effect of vibronic coupling (orbit–lattice interaction), which produces a mixing between the low-lying electronic states with the emission and absorption of phonons of varying energies, is considered to explain the observed temperature dependence of Mossbauer Quadrupole Splitting of Fe2+ ions in CsCoCl3 over 22 to 300 K. The various lattice dynamical parameters are estimated and then Quadrupole Splitting is explicitly calculated as a function of temperature. One obtains a reasonably good agreement with the experimental data, which shows that the vibrating lattice model is quite realistic and important.
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Fe2+ Quadrupole Splitting in Dolomite under Orbit‐Lattice Interaction. A mossbauer study
physica status solidi (b), 1993Co-Authors: T. P. Sinha, S. Ganguli, M. BhattacharyaAbstract:The temperature dependence of the Mossbauer Quadrupole Splitting of Fe 2+ ions in dolomite is theoretically analysed from 12 to 295 K by invoking orbit-lattice interaction (dynamic crystal field potential through vibronic coupling). This results in a good agreement between theoretical and experimental data. It is shown that the orbit-lattice interaction is important for ferrous ions and its effect should be duly included in the interpretation of Mossbauer observables as a function of temperature
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orbit lattice interaction and mossbauer Quadrupole Splitting of ferrous ions in ferrous diphenyl sulfoxide chlorate
Physical Review B, 1993Co-Authors: T. P. SinhaAbstract:The effect of vibronic coupling between low-lying electronic states on the temperature dependence of the Mossbauer Quadrupole Splitting of Fe 2+ ions in Fe[(C 6 H 5 ) 2 SO] 6 (ClO 4 ) 2 is theoretically analyzed over 4.2 to 340 K. This results in a better agreement between theoretical and experimental data. It shows that the orbit-lattice interaction is important for ferrous ions and its effect should be duly included in the interpretation of Mossbauer observables as a function of temperature
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Electronic states and Fe2+ Quadrupole Splitting in Fe[(CH3)2SO]6(CIO4)2 under orbit-lattice interaction
Physica B: Condensed Matter, 1993Co-Authors: T. P. SinhaAbstract:Abstract The effect of orbit-lattice interaction which produces a mixing between the low-lying electronic states with the emission and absorption of phonons of varying energies is considered to explain the observed temperature dependence of Mossbauer Quadrupole Splitting of 57 Fe 2+ ions in Fe[(CH 3 ) 2 SO] 6 (CIO 4 ) 2 . The various lattice dynamical parameters are estimated and then Quadrupole Splitting is explicitly calculated as a function of temperature. One obtains a reasonably good agreement with the experimental data which shows that the vibrating lattice model is quite realistic and important.
M. I. Oshtrakh - One of the best experts on this subject based on the ideXlab platform.
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variations in Quadrupole Splitting of the 57fe in the m1 and m2 sites of meteoritic olivines with different origin
Hyperfine Interactions, 2013Co-Authors: M. I. Oshtrakh, E V Petrova, V I Grokhovsky, V. A. SemionkinAbstract:A comparative study of meteoritic olivine in bulk samples of Farmington L5 and Tsarev L5 ordinary chondrites and extracted from Omolon and Seymchan the main-group pallasites was performed using Mossbauer spectroscopy with a high velocity resolution. Mossbauer spectra for each specimen were measured at 295 and 90 K. Mossbauer spectral components related to the 57Fe in crystallographically non-equivalent sites M1 and M2 in olivines were determined and their Mossbauer hyperfine parameters were evaluated. It was found small variations of Quadrupole Splitting for the 57Fe in both the M1 and M2 sites of olivines in bulk ordinary chondrites and olivines extracted from pallasites.
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57 Fe Quadrupole Splitting and isomer shift in various oxyhemoglobins: study using Mössbauer spectroscopy
Hyperfine Interactions, 2010Co-Authors: M. I. Oshtrakh, A. L. Berkovsky, A. Kumar, S. Kundu, A. V. Vinogradov, T. S. Konstantinova, V. A. SemionkinAbstract:A comparative study of normal human, rabbit and pig oxyhemoglobins and oxyhemoglobin from patients with chronic myeloleukemia and multiple myeloma using Mossbauer spectroscopy with a high velocity resolution demonstrated small variations of the 57Fe Quadrupole Splitting and isomer shift. These variations may be a result of small structural differences in the heme iron stereochemistry of various hemoglobins.
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The DFT–DVM theoretical study of the differences of Quadrupole Splitting and the iron electronic structure for the rough heme models for α- and β-subunits in deoxyhemoglobin and for deoxymyoglobin
Hyperfine Interactions, 2008Co-Authors: E. I. Yuryeva, M. I. OshtrakhAbstract:Quantum chemical calculations of the iron electron structure and (57)Fe Quadrupole Splitting were made by density functional theory and X alpha discrete variation method for the rough heme models for alpha- and beta-subunits in deoxyhemoglobin and for deoxymyoglobin accounting stereochemical differences of the active sites in native proteins. The calculations revealed differences of Quadrupole Splitting temperature dependences for three models indicating sensitivity of Quadrupole Splitting and Fe(II) electronic structure to small variations of iron stereochemistry
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The DFT-DVM theoretical study of the differences of Quadrupole Splitting and the iron electronic structure for the rough heme models for α- and β-subunits in deoxyhemoglobin and for deoxymyoglobin
Hyperfine Interactions, 2008Co-Authors: E. I. Yuryeva, M. I. OshtrakhAbstract:Quantum chemical calculations of the iron electron structure and 57Fe Quadrupole Splitting were made by density functional theory and Xα discrete variation method for the rough heme models for α- and β-subunits in deoxyhemoglobin and for deoxymyoglobin accounting stereochemical differences of the active sites in native proteins. The calculations revealed differences of Quadrupole Splitting temperature dependences for three models indicating sensitivity of Quadrupole Splitting and Fe(II) electronic structure to small variations of iron stereochemistry.
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Differences of the Quadrupole Splitting and iron electronic structure for the heme models for α and β subunits in deoxyhemoglobin and for deoxymyoglobin: Quantum-chemical calculations by the DFT-DVM method
Bulletin of the Russian Academy of Sciences: Physics, 2007Co-Authors: E. I. Yur’eva, M. I. OshtrakhAbstract:The quantum-chemical calculation of the iron electronic structure and 57Fe Quadrupole Splitting have been performed by the DFT-DVM method for rough heme models for α and β subunits in deoxyhemoglobin and for deoxymyoglobine, which take into account stereochemical differences of the active cites in native proteins. The calculations revealed differences in the temperature dependences of Quadrupole Splitting for the three models, indicating sensitivity of the Quadrupole Splitting and Fe(II) electronic structure to small stereochemical variations in the nearest iron environment. The theoretical results confirmed the possibility of approximating experimental Mossbauer spectra of tetrameric hemoglobins with allowance for the nonequivalence of the Fe(II) electronic structure in nonidentical subunits.
V. A. Semionkin - One of the best experts on this subject based on the ideXlab platform.
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variations in Quadrupole Splitting of the 57fe in the m1 and m2 sites of meteoritic olivines with different origin
Hyperfine Interactions, 2013Co-Authors: M. I. Oshtrakh, E V Petrova, V I Grokhovsky, V. A. SemionkinAbstract:A comparative study of meteoritic olivine in bulk samples of Farmington L5 and Tsarev L5 ordinary chondrites and extracted from Omolon and Seymchan the main-group pallasites was performed using Mossbauer spectroscopy with a high velocity resolution. Mossbauer spectra for each specimen were measured at 295 and 90 K. Mossbauer spectral components related to the 57Fe in crystallographically non-equivalent sites M1 and M2 in olivines were determined and their Mossbauer hyperfine parameters were evaluated. It was found small variations of Quadrupole Splitting for the 57Fe in both the M1 and M2 sites of olivines in bulk ordinary chondrites and olivines extracted from pallasites.
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57 Fe Quadrupole Splitting and isomer shift in various oxyhemoglobins: study using Mössbauer spectroscopy
Hyperfine Interactions, 2010Co-Authors: M. I. Oshtrakh, A. L. Berkovsky, A. Kumar, S. Kundu, A. V. Vinogradov, T. S. Konstantinova, V. A. SemionkinAbstract:A comparative study of normal human, rabbit and pig oxyhemoglobins and oxyhemoglobin from patients with chronic myeloleukemia and multiple myeloma using Mossbauer spectroscopy with a high velocity resolution demonstrated small variations of the 57Fe Quadrupole Splitting and isomer shift. These variations may be a result of small structural differences in the heme iron stereochemistry of various hemoglobins.
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the features of mossbauer spectra of hemoglobins approximation by superposition of Quadrupole doublets or by Quadrupole Splitting distribution
Hyperfine Interactions, 2005Co-Authors: M. I. Oshtrakh, V. A. SemionkinAbstract:Mossbauer spectra of hemoglobins have some features in the range of liquid nitrogen temperature: a non-Lorentzian asymmetric line shape for oxyhemoglobins and symmetric Lorentzian line shape for deoxyhemoglobins. A comparison of the approximation of the hemoglobin Mossbauer spectra by a superposition of two Quadrupole doublets and by a distribution of the Quadrupole Splitting demonstrates that a superposition of two Quadrupole doublets is more reliable and may reflect the non-equivalent iron electronic structure and the stereochemistry in the α- and β-subunits of hemoglobin tetramers.
Jamil Hantash - One of the best experts on this subject based on the ideXlab platform.
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basnf4 fast ion conductor variations versus the method of preparation and anomalous temperature variation of the Quadrupole Splitting
Hyperfine Interactions, 2006Co-Authors: Jamil Hantash, Alan Bartlett, Georges Denes, Abdualhafeed Muntasar, Philip OldfieldAbstract:A new method of preparation of high performance fluoride ion conductor, BaSnF4, by water leaching of newly discovered barium tin(II) chloride fluorides, has been designed, and the materials have been studied and compared to the solid prepared by the usual dry method. The unit-cell parameters and crystallite dimensions were found to vary with the method of preparation. In addition, the crystallite dimensions were found to be highly anisotropic for the samples obtained by the wet method. The Mossbauer spectrum is made of a large tin(II) Quadrupole doublet, and a broad tin(IV) oxide peak due to surface oxidation. The tin(II) spectrum is in agreement with covalently bonded tin(II) having a strongly stereoactive lone pair. An unusually high dependence of the Quadrupole Splitting at low temperatures was observed (5.8 times larger than for α-SnF2).
A. Sklyarova - One of the best experts on this subject based on the ideXlab platform.
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57Fe Mössbauer study of a secondary phase in FeSe1−x with a large Quadrupole Splitting
Hyperfine Interactions, 2014Co-Authors: A. Sklyarova, Johan Lindén, Girish C. Tewari, Eeva-leena Rautama, Maarit KarppinenAbstract:We have studied the hyperfine interactions in samples belonging to the Fe-Se system. Several samples with various concentrations of selenium were synthesized and investigated. The objective was to find synthesis conditions increasing the concentration of a secondary Fe-Se phase with a rather large Quadrupole Splitting of ~1.7 mm/s. At Tm ≈ 104 K this secondary phase undergoes a magnetic ordering.
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57fe mossbauer study of a secondary phase in fese1 x with a large Quadrupole Splitting
Hyperfine Interactions, 2014Co-Authors: A. Sklyarova, Johan Lindén, Girish C. Tewari, Eeva-leena Rautama, Maarit KarppinenAbstract:We have studied the hyperfine interactions in samples belonging to the Fe-Se system. Several samples with various concentrations of selenium were synthesized and investigated. The objective was to find synthesis conditions increasing the concentration of a secondary Fe-Se phase with a rather large Quadrupole Splitting of ~1.7 mm/s. At Tm ≈ 104 K this secondary phase undergoes a magnetic ordering.
