Ligand Energy Controls the Heme-Fe Valence in Aqueous Myoglobins

Harada, Yoshihisa; Taguchi, M.; Miyajima, Yoshiharu; Tokushima, Takashi; Horikawa, Yoko; Chainani, A.; Shiro, Yoshitsugu; Senba, Yasunori; Ohashi, Haruhiko; Fukuyama, Hidetoshi; Shin, Shik

doi:10.1143/jpsj.78.044802

Cited by 27 publications

(25 citation statements)

References 32 publications

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“…The Mn-3d electrons are delocalized and strongly hybridized with the O-2p orbital in the wide energy range when the CT energy is negative. These mechanism were reported in previous paper [10].…”

Section: Resultssupporting

confidence: 87%

X-Ray Spectroscopic Studies of A-Site Ordered Perovskite LaMn3B4O12(B=V, Cr)

Mizumaki

Saito

Uozumi

et al. 2012

e-J. Surf. Sci. Nanotechnol.

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We investigated the electronic structure of LaMn3V4O12 (LMVO) and LaMn3Cr4O12 (LMCO) by X-ray absorption spectroscopy (XAS) and resonant X-ray emission spectroscopy (RXES) measurements around Mn 2p edges. The Mn 2p-XAS spectra showed that the Mn valence is trivalent for LMCO and divalent for LMVO. These results indicate that the A ′ -site can accommodate not only Jahn-Teller ions but also non-Jahn-Teller ions. The Mn 2p-RXES spectra showed the difference of the hybridization between Mn-3d and O-2p orbitals. According to theoretical calculation results, LMCO is candidates for the negative charge transfer energy compound.

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Section: Resultssupporting

confidence: 87%

X-Ray Spectroscopic Studies of A-Site Ordered Perovskite LaMn3B4O12(B=V, Cr)

Mizumaki

Saito

Uozumi

et al. 2012

e-J. Surf. Sci. Nanotechnol.

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“…We also note that a still larger ðpdÞ (¼ À5:44= ffiffi ffi 3 p eV ¼ À3:18 eV) is assumed in the cluster model analysis of the Fe 2p resonant X-ray emission of cyanomet myoglobin. 30) …”

Section: Energy Levels Of Divalent Fe Cyanidesmentioning

confidence: 99%

Competition between Backbonding and Electron Correlation in Fe Cyanides

Okada

2010

J. Phys. Soc. Jpn.

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We calculate the Fe 2p X-ray absorption spectrum (XAS) of an Fe(CN) 6 model cluster in order to understand the electron correlation effect on the electronic states of RbMn[Fe(CN) 6 ], K 3 Fe(CN) 6 , and K 4 Fe(CN) 6 . The Hamiltonian includes the Fe on-site Coulomb interaction and the interatomic electron hopping terms, and it has some adjustable parameters, such as the Fe 3d-3d Coulomb interaction strength (U) and the Fe 3d-C 2p and C 2p-N 2p hopping strengths. We diagonalize the Hamiltonian using the basis wavefunctions that are constructed according to configuration interaction and determine the numerical values of the relevant physical parameters so as to reproduce the observed Fe 2p XAS. As shown in the studies performed so far, backbonding, in other words, the charge transfer from Fe 3d to ligand p orbitals, is also important in the present study. On the other hand, we point out that U plays a role of suppressing excess charge transfer. Therefore, the observed Fe 2p XAS of the Fe cyanides is realized by the competition between backbonding and electron correlation. We also note the importance of considering the realistic electronic structure of the cyano group in reproducing the Fe 2p XAS as well as the Fe 1s XAS.

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“…A problem is radiation damage of biological specimens, and as a beginning, experiments were made on rather stable molecules such as myoglobin, at 77 K. Shifting the sample along the beam allows one to investigate undamaged molecules. The high -and low -spin confi guration of the center iron of the heme site of myoglobin could be clearly distinguished [154] . Due to the resonant optical behavior at the core shell absorption edges of elements, it has been shown that Cherenkov radiation can be generated in comparably narrow spectral segments in the soft X -ray region [155] .…”

Section: Selected X -Ray Surface/interface Analysis Methodsmentioning

confidence: 98%

Tailoring of Interfaces for the Photoelectrochemical Conversion of Solar Energy

Lewerenz

2010

Advances in Electrochemical Sciences and Engineering

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IntroductionIn the search for terrestrially applicable carbon -neutral energy sources, photoelectrochemical systems exhibit several advantageous features: examples are the facilitated junction formation at the electrolyte interface, the scalability typically achieved by self -organized processes at the solid -liquid boundary [1, 2] , lowtemperature processing, and the in situ preparation and optimization of specifi c interface conditions [3,4] . In addition, photoelectrochemical solar cells can operate in the photovoltaic [5 -9] as well as in the photoelectrocatalytic [10 -14] mode. The latter is of particular importance because global energy consumption is clearly dominated by the use of fuels compared to electricity [15] . Due to stability issues when operating a solar cell at a reactive phase boundary, such as a semiconductor -electrolyte contact, photovoltaic electrochemical solar cells have technologically not been realized despite the existence of systems that have demonstrated extended stability under operation [4,7] . As limited thermodynamic stability is also a factor for solar fuel generating devices, a general strategy is needed for the future implementation of photoelectrochemical solar energy conversion systems.At the present stage of the fi eld, a multifaceted approach appears mandatory which focuses on fundamental research regarding charge and excitation energy transfer [16 -18] , materials development, particularly in conjunction with the developments in nanoscience [19 -23] , and control of interface behavior [24 -26] . This latter aspect will be the focus of the present chapter.Besides the investigation of fundamental properties of the solid -liquid interface, the situation with a rapidly deteriorating atmospheric situation [27] also demands the use of rational screening methods for the identifi cation and examination of novel photoactive materials, material combinations, and composites [28 -30] . It is obvious that a large -scale and international research and development effort is 2 Advances in Electrochemical Science and Engineering. Edited

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Ligand Energy Controls the Heme-Fe Valence in Aqueous Myoglobins

Cited by 27 publications

References 32 publications

X-Ray Spectroscopic Studies of <i>A</i>-Site Ordered Perovskite LaMn<sub>3</sub><i>B</i><sub>4</sub>O<sub>12</sub>(<i>B</i>=V, Cr)

X-Ray Spectroscopic Studies of <i>A</i>-Site Ordered Perovskite LaMn<sub>3</sub><i>B</i><sub>4</sub>O<sub>12</sub>(<i>B</i>=V, Cr)

Competition between Backbonding and Electron Correlation in Fe Cyanides

Tailoring of Interfaces for the Photoelectrochemical Conversion of Solar Energy

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