Topic
Valence (chemistry)
About: Valence (chemistry) is a research topic. Over the lifetime, 24937 publications have been published within this topic receiving 645252 citations. The topic is also known as: valency.
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TL;DR: In this article, the new compounds La1−xMxMnO3 (0.05 ⩽ x⩽ 0.4), LaMnNO3.15, La0.8Na 0.8Rb 0.
137 citations
TL;DR: In this article, the conduction and valence band edges of Ta3N5 were determined from the photocurrent voltage response for the reduction of H+ to H2 and the oxidation of H2O to O2.
Abstract: Tantalum nitride (Ta3N5) thin film is investigated as a visible light-driven photoelectrode material. The photoelectrochemical properties of the material are investigated on the basis of cyclic voltammograms and current−time curves, and the conduction and valence band edges of Ta3N5 are determined from the photocurrent voltage response. The potentials of the conduction and valence bands are found to be satisfactory for the reduction of H+ to H2 and the oxidation of H2O to O2. Anodic photocurrent associated with the oxidation of water is obtained under visible-light irradiation, although the Ta3N5 itself undergoes simultaneous oxidation. Through sustained photoinduced redox cycling on the Ta3N5 electrode in aqueous Fe(CN)63-/Fe(CN)64- solution, Ta3N5 thin film is demonstrated to function as a stable electrode for generating electric current under visible light.
137 citations
TL;DR: In this article, a multireference perturbation theory with complete active space self-consistent field (CASSCF) reference functions was applied to the study of the valence π→π* excited states of benzene and naphthalene.
Abstract: Multireference perturbation theory with complete active space self‐consistent field (CASSCF) reference functions was applied to the study of the valence π→π* excited states of benzene and naphthalene. The eigenvectors and eigenvalues of CASSCF with valence π active orbitals satisfy pairing properties for the alternant hydrocarbons to a good approximation. The excited states of polyacenes are classified into the covalent minus states and ionic plus states with the use of the alternancy symmetry. The present theory satisfactorily describes the ordering of low‐lying valence π→π* excited states. The overall accuracy of the present approach is surprisingly high. We were able to predict the valence excitation energies with an accuracy of 0.27 eV for singlet u states and of 0.52 eV or better for singlet g states of naphthalene. Our predicted triplet states spectrum provides a consistent assignment of the triplet–triplet absorption spectrum of naphthalene. For benzene we were able to predict the valence excitatio...
137 citations
TL;DR: In this paper, the Breit-Pauli B-spline R-matrix method was applied to the treatment of e-Ar collisions and an individually optimized, term-dependent set of non-orthogonal valence orbitals was used to account for the strong term dependence in the one-electron orbitals.
Abstract: We have applied the Breit–Pauli B-spline R-matrix method described earlier (J. Phys. B: At. Mol. Opt. Phys. 37 (2004) 2173) to the treatment of e–Ar collisions. An individually optimized, term-dependent set of non-orthogonal valence orbitals is used to account for the strong term dependence in the one-electron orbitals. Concentrating on the near-threshold regime for excitation of the 3p54s manifold, we obtain excellent agreement with benchmark experimental data for the production of metastable atoms and for excitation of the VUV-emitting J = 1 levels. A detailed partial-wave resolved resonance analysis shows that many of the structures listed by Buckman and Clark (Rev. Mod. Phys. 66 (1994) 539) are composed of overlapping resonances. These, together with their principal components and decay channels, are identified and, in some cases, alternative classifications are suggested.
137 citations
TL;DR: The occupied and unoccupied valence-band structure of Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7/ is probed with photoemission, inverse photo-emission and near-edge x-ray absorption as discussed by the authors.
Abstract: The occupied and unoccupied valence-band structure of Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7/ is probed with photoemission, inverse photoemission, and near-edge x-ray absorption. The Cu 3d and O 2p states nearly coincide, thereby maximizing their interaction. The occupied states are shifted down by 2 eV relative to ground-state band calculations, indicating localization and a Coulomb interaction U>2 eV. The band width is 10 eV with the top of the band at E/sub F/+2.5 eV. Cu is found in the 2+ oxidation state. O has 2p holes which are assigned to specific oxygen atoms.
137 citations