First Principles Estimation of Geochemically Important Transition Metal Oxide Properties

Chen, Ying; Bylaska, Eric J.; Weare, John H.

doi:10.1002/9781118845226.ch4

Cited by 13 publications

(20 citation statements)

References 125 publications

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“…The symmetry of the spin-up and spin-down PDOS is related to the polarization of spin moment of transition metal (V atom). 36 The un-symmetric spin state (polarized state) PDOS inside the bandgap suggests the absence of surface V atoms in certain spin direction, and such surface termination influences the adjacent O atoms to become polarized too. 36 Thus, the observed filled state inside the bandgap is mainly composed of V 3d and O 2p orbitals.…”

Section: Resultsmentioning

confidence: 99%

An investigation on the role of W doping in BiVO₄ photoanodes used for solar water splitting

Zhao

Chen

et al. 2018

Phys. Chem. Chem. Phys.

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n-Type doping has been widely employed to enhance the performance of a photoanode in a photoelectrochemical cell used for water splitting. However, little is known about how doping affects the catalytic activity during surface catalysis. Herein, we took BiVO4 as an example to investigate the effect of doping on surface catalysis from both experimental and theoretical perspectives. To enable an impartial comparison, we have prepared planar BiVO4 thin films with and without W doping. It was found that W doping had no obvious effect on the morphology, crystallinity, and light absorption of the film; however, the photocurrent was significantly enhanced upon W doping. This enhancement is contributed by two important factors: better charge separation efficiency and improved surface charge transfer efficiency. Electrochemical analysis reveals that W doping lowers the surface charge transfer resistance and forms active surface states, facilitating charge transfer. Theoretical analysis shows that W doping activates the V atoms to be reactive sites. Moreover, the adsorption energies and distance between adsorption species (OHads, Oads, and OOHads) involved in the water splitting process become more favorable for surface charge transfer. The current study provides an insight into the roles of W doping in BiVO4, especially during surface catalysis.

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Section: Resultsmentioning

confidence: 99%

An investigation on the role of W doping in BiVO₄ photoanodes used for solar water splitting

Zhao

Chen

et al. 2018

Phys. Chem. Chem. Phys.

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“…To accommodate the more rapid variation of the ψ functions near the atomic nucleus the finite element grid is adapted within the domain, see Figure 1. This is an essential feature of atomic and molecular electronic structure calculations [16,38,17] that do not introduce pseudopotentials [18]. Figure 1: A representation of the finite element grid used in calculation.…”

Section: Overview Of Numerical Methods (Fem)mentioning

confidence: 99%

“…However, at α = 0 this follows directly from (18). Using the Implicit Function Theorem for a small range of α, there is an E = E (α) satisfying the mass equation.…”

Section: Construction Of the Local Branch Under The Symmetry Assumptionmentioning

confidence: 95%

Symmetry Breaking in Density Functional Theory due to Dirac Exchange for a Hydrogen Molecule

Holst,

Hu,

et al. 2019

Preprint

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We study symmetry breaking in the mean field solutions to the 2 electron hydrogen molecule within Kohn Sham (KS) local spin density function theory with Dirac exchange (the XLDA model). This simplified model shows behavior related to that of the (KS) spin density functional theory (SDFT) predictions in condensed and molecular systems. The Kohn Sham solutions to the constrained SDFT variation problem undergo spontaneous symmetry breaking as the relative strength of the non-convex exchange term increases. This results in the change of the molecular ground state from a paramagnetic state to an antiferromagnetic ground states and a stationary symmetric delocalized 1st excited state. We further characterize the limiting behavior of the minimizer when the strength of the exchange term goes to infinity. This leads to further bifurcations and highly localized states with varying character. The stability of the various solution classes is demonstrated by Hessian analysis. Finite element numerical results provide support for the formal conjectures.

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“…The pseudopotential plane-wave method and the related pseudopotential uniform grid realspace method is a popular, fast, and efficient way to implement KS-DFT 29,45,83,109,235,250,251,[282][283][284][285][286][287][288][289][290][291][292][293][294][295][296][297][298][299] .…”

Section: Newton-krylov Solver For Coupled-cluster Equationsmentioning

confidence: 99%

From NWChem to NWChemEx: Evolving with the Computational Chemistry Landscape

et al. 2021

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Since the advent of the first computers, chemists have been at the forefront of using computers to understand and solve complex chemical problems. As the hardware and software have evolved, so have the theoretical and computational chemistry methods and algorithms. Parallel computers clearly changed the common computing paradigm in the late 1970s and 80s, and the field has again seen a paradigm shift with the advent of graphical processing units. This review explores the challenges and some of the solutions in transforming software from the terascale to the petascale and now to the upcoming exascale computers. While discussing the field in general, NWChem and its redesign, NWChemEx, will be highlighted as one of the early co-design projects to take advantage of massively parallel computers and emerging software standards to enable large scientific challenges to be tackled.

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First Principles Estimation of Geochemically Important Transition Metal Oxide Properties

Cited by 13 publications

References 125 publications

An investigation on the role of W doping in BiVO₄ photoanodes used for solar water splitting

An investigation on the role of W doping in BiVO₄ photoanodes used for solar water splitting

Symmetry Breaking in Density Functional Theory due to Dirac Exchange for a Hydrogen Molecule

From NWChem to NWChemEx: Evolving with the Computational Chemistry Landscape

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First Principles Estimation of Geochemically Important Transition Metal Oxide Properties

Cited by 13 publications

References 125 publications

An investigation on the role of W doping in BiVO4 photoanodes used for solar water splitting

An investigation on the role of W doping in BiVO4 photoanodes used for solar water splitting

Symmetry Breaking in Density Functional Theory due to Dirac Exchange for a Hydrogen Molecule

From NWChem to NWChemEx: Evolving with the Computational Chemistry Landscape

Contact Info

Product

Resources

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An investigation on the role of W doping in BiVO₄ photoanodes used for solar water splitting

An investigation on the role of W doping in BiVO₄ photoanodes used for solar water splitting