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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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Journal ArticleDOI
TL;DR: In this article, the absolute yields of the secondary ions MeO ± n (n = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 30, 31, 34, 35, 34) were derived from 15 oxidized metal surfaces in a UHV mass spectrometer.

133 citations

Journal ArticleDOI
TL;DR: By ESR technique, the formation of adsorbed O2− and O− on TiSiO2, VSiO2 and Vγ-Al2O3 has been studied as mentioned in this paper.

133 citations

Journal ArticleDOI
Wenjun Luo1, Jiajia Wang1, Xin Zhao1, Zong-Yan Zhao1, Zhaosheng Li1, Zhigang Zou1 
TL;DR: Results of theoretical calculation indicated that a higher formation energy and lower solubility of impurity ions led to serious SnO(2) segregation on the surface of the Sn(4+)-doped BiVO(4) thin film, which was the main reason for the poor performance of Sn-doped biVO( 4).
Abstract: Photoelectrochemical water splitting is an attractive method to produce H2 fuel from solar energy and water. Ion doping with higher valence states was used widely to enhance the photocurrent of an n-type oxide semiconductor. In this study, the different doping sites and the photoelectrochemical properties of Mo6+, W6+ and Sn4+-doped BiVO4 were studied systematically. The results suggested that Mo6+ or W6+-doped BiVO4 had a much higher photocurrent while the photocurrent of Sn4+-doped BiVO4 did not change obviously. Raman and XPS were used to identify the doping sites in the BiVO4 crystal lattice. It was found that Mo or W substituted V sites but Sn did not substitute Bi sites. Results of theoretical calculation indicated that a higher formation energy and lower solubility of impurity ions led to serious SnO2 segregation on the surface of the Sn4+-doped BiVO4 thin film, which was the main reason for the poor performance of Sn-doped BiVO4. The higher formation energy of Sn4+ came from the large mismatch of ion radius and different outer shell electron distribution. These results can offer guidance in choosing suitable doping ions for other semiconductor photoelectrodes.

133 citations

Journal ArticleDOI
TL;DR: In this article, a systematic study of the accuracy of structures and frequencies of 33 small radical molecules is presented as predicted by Hartree−Fock (HF) theory, second-order Moller−Plesset (MP2), coupled-cluster singles and doubles (CCSD), and gradient-corrected density functional theory with 3-parameter exact exchange mixing (B3LYP).
Abstract: A systematic study of the accuracy of structures and frequencies of 33 small radical molecules is presented as predicted by Hartree−Fock (HF) theory, second-order Moller−Plesset (MP2) theory, coupled-cluster singles and doubles (CCSD) theory, coupled-cluster singles and doubles with perturbational triples correction [CCSD(T)] theory, and gradient-corrected density functional theory with 3-parameter exact exchange mixing (B3LYP). For all methods, calculations were carried out using the Pople 6-31G**, the correlation-consistent polarized valence double-ζ (cc-pVDZ), and the correlation-consistent polarized valence triple-ζ (cc-pVTZ) basis sets. While basis set effects were moderate, large differences in the performance of the different methods were found. Due primarily to artifactual symmetry breaking and orbital instabilities, both restricted and unrestricted HF and MP2 perform too erratically to be acceptable. CCSD with either restricted or unrestricted orbitals yields results in generally good agreement w...

133 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,521
20222,997
2021616
2020611
2019584
2018577