Proton Dynamics in KDP Studied by ESR of SeO<sub>4</sub><sup>3-</sup>

Hukuda, Kenzi

doi:10.1143/jpsj.38.150

Cited by 30 publications

(6 citation statements)

References 7 publications

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“…In short, the results obtained are fairly similar to those described above for the AsO 4 4center. One observes a well defined quintet-triplet transition in the EPR spectra [14][15][16]30], similar to that shown in Fig. 1 above, that provide direct evidence for the order-disorder behavior.…”

Section: (B) Evidence Of the Coexistence Using Seo 3-4supporting

confidence: 63%

“…Extensive EPR [14][15][16][17][18][19][20][21][22]30] and ENDOR [16,30,34,38] studies have also been carried out on the KDP family using the SeO 4 3probe. In short, the results obtained are fairly similar to those described above for the AsO 4 4center.…”

Section: (B) Evidence Of the Coexistence Using Seo 3-4mentioning

confidence: 99%

“…The present undertaking discusses the utilization of electron paramagnetic resonance (EPR) spectroscopy for investigating dielectric solids that are diamagnetic in their native state, but can be made slightly paramagnetic by lightly doping them with transition ions, such as Fe 3+ , as pioneered by Müller [2][3][4][5][6][7], or by using molecular probes such as the CrO 4 3-(Cr 5+ ) ion [1,[8][9][10][11][12][13], SeO 4 3radical [14][15][16][17][18][19][20][21][22] and the AsO 4 4center [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. While Müller's studies using Fe 3+ as a probe in SrTiO 3 and LaAlO 3 are considered as some of the classic examples of the power of EPR technique in probing microscopic mechanisms of phase transitions in the perovskites [2][3]…”

Section: Introductionmentioning

confidence: 99%

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Coexistence of Order–Disorder and Displacive Behavior of KH2PO4 and Analogs from Electron Paramagnetic Resonance

Dalal

2007

High Tc Superconductors and Related Transition Metal Oxides

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An early report by Müller et al. [Phys Rev Lett 36:1504] on the electron paramagnetic resonance (EPR) studies of slow (100 MHz-range) molecular dynamics in ferroelectric crystals has proven to be pioneering in the field of phase transitions. Subsequent studies over the last 30 years have extended this methodology and utilized it for unraveling microscopic mechanism(s) of ferroelectric and antiferroelectric phase transitions, especially for the KH 2 PO 4 (KDP) family. We here discuss these EPR as well as some related electron nuclear double resonance data, utilizing the conjecture that an anomaly in the isotropic part of the electron Zeeman tensor (g iso ) or of hyperfine coupling, a iso , implies an electronic instability. It is concluded that the phase transitions of the KDPfamily exhibit an order-disorder character as well as instability (displacive behavior). This is in conformity with recent high-resolution NMR data, but in contrast with the notion that these materials are model order-disorder systems.

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Section: (B) Evidence Of the Coexistence Using Seo 3-4supporting

confidence: 63%

Section: (B) Evidence Of the Coexistence Using Seo 3-4mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Coexistence of Order–Disorder and Displacive Behavior of KH2PO4 and Analogs from Electron Paramagnetic Resonance

Dalal

2007

High Tc Superconductors and Related Transition Metal Oxides

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“…The unique A( 77 Se) axis of the SeO 4 3– radical is approximately along the S–O2 bond direction in the gypsum structure (Tables and ). The interaction of the SeO 4 3– radical with a single proton observed in both Se 4+ - and Se 6+ -doped gypsum after gamma-ray irradiation (Figure a,b) is distinct from its close analogue in KH 2 (PO 4 ), which is characterized by interaction with two equivalent protons . In gypsum, each O2 atom is linked, via hydrogen bonds, to two almost equivalent protons from two neighboring water molecules.…”

Section: Resultsmentioning

confidence: 90%

Sequestration of Selenite and Selenate in Gypsum (CaSO₄·2H₂O): Insights from the Single-Crystal Electron Paramagnetic Resonance Spectroscopy and Synchrotron X-ray Absorption Spectroscopy Study

Lin

Chen

Feng

et al. 2020

Environ. Sci. Technol.

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Gypsum is the most common sulfate mineral on Earth's surface and is the dominant solid byproduct in a wide variety of mining and industrial processes, thus representing a major source for heavy metal(loid) contamination, including selenium. Gypsum crystals grown from the gel diffusion technique in 0.02 M Na 2 SeO 4 solution at pH 7.5 and 0.02 M Na 2 SeO 3 solutions at pH 7.5 and 9.0 contain 828, 5198, and 5955 ppm Se, respectively. Synchrotron Se K-edge X-ray absorption spectroscopic analyses show that selenite and selenate are the dominant species in Se 4+ -and Se 6+ -doped gypsum, respectively. The singlecrystal EPR spectra of Se 4+ -and Se 6+ -doped gypsum after gammaray irradiation reveal five selenium-centered oxyradicals: SeO 2 − (I), SeO 2 − (II), SeO 2 − (III), SeO 3 − , and HSeO 4 2− . The former three radicals provide unequivocal evidence for the substitution of their paramagnetic precursor SeO 3 2− for SO 4 2− in the gypsum structure, while the latter two confirm the replacement of SeO 4 2− for SO 4 2− . These results demonstrate that gypsum has a significant capacity for sequestrating both selenite and selenate in the structure but has a marked preference for the former, thus confirming important controls on the mobility and bioavailability of selenium oxyanions and pointing to optimal applications of gypsum for remediating selenium contamination under neutral to alkaline conditions.

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“…[13][14][15][16] We note that in the present model the barrier height is estimated by calculating the total energy of the cluster via varying only the position of the probe H atom, and keeping all other atoms fixed at their (average) crystallographic positions. Of course this value may be different from the barrier created by all of the other atoms and seen by a "fixed" hydrogen atom at the minimum.…”

Section: Discussionmentioning

confidence: 99%

An ab-initio study of the potential energy surface for the O-H—O bond in KH₂PO₄

Hao

Dalal

1992

Ferroelectrics

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A methodology is presented for carrying out ab-initio molecular orbital calculation of the potential energy surface as a function of position of the H atom in the 0 -H ---0 bonds of KH,PO, (KDP). The calculations employ the Hartree-Fock Self-Consistent-Field (SCF) approach utilizing the Linear Combination of Atomic Orbital for Molecular Orbital (LCAOMO) procedure with basis in Gaussian form. This approach seems to yield a reliable representation of double-minimum potential well for the 0-H---0 bond in KDP, as judged from the agreement between the predicted (0.3604 A) and experimental (0.3674 A) values for the separation between the two equilibrium positions of the H atom along the 0---0 direction. The calculated value of the barrier height (0.08 eV) helps clarify some earlier spectroscopic data on the activation energy for the motion of the H-atom in the 0-H---0 bond in KDP. The same methodology should be applicable for investigating the possible double-minimum wells for the heavier atoms in the KDP-type of ferroelectrics and antiferroelectrics.

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Proton Dynamics in KDP Studied by ESR of SeO₄^3-

Cited by 30 publications

References 7 publications

Coexistence of Order–Disorder and Displacive Behavior of KH2PO4 and Analogs from Electron Paramagnetic Resonance

Coexistence of Order–Disorder and Displacive Behavior of KH2PO4 and Analogs from Electron Paramagnetic Resonance

Sequestration of Selenite and Selenate in Gypsum (CaSO₄·2H₂O): Insights from the Single-Crystal Electron Paramagnetic Resonance Spectroscopy and Synchrotron X-ray Absorption Spectroscopy Study

An ab-initio study of the potential energy surface for the O-H—O bond in KH₂PO₄

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Proton Dynamics in KDP Studied by ESR of SeO43-

Cited by 30 publications

References 7 publications

Coexistence of Order–Disorder and Displacive Behavior of KH2PO4 and Analogs from Electron Paramagnetic Resonance

Coexistence of Order–Disorder and Displacive Behavior of KH2PO4 and Analogs from Electron Paramagnetic Resonance

Sequestration of Selenite and Selenate in Gypsum (CaSO4·2H2O): Insights from the Single-Crystal Electron Paramagnetic Resonance Spectroscopy and Synchrotron X-ray Absorption Spectroscopy Study

An ab-initio study of the potential energy surface for the O-H—O bond in KH2PO4

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Product

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Proton Dynamics in KDP Studied by ESR of SeO₄^3-

Sequestration of Selenite and Selenate in Gypsum (CaSO₄·2H₂O): Insights from the Single-Crystal Electron Paramagnetic Resonance Spectroscopy and Synchrotron X-ray Absorption Spectroscopy Study

An ab-initio study of the potential energy surface for the O-H—O bond in KH₂PO₄