Cyclic cluster study of water adsorption structures on the MgO(100) surface

Jug, Karl; Heidberg, Bettina; Bredow, Thomas

doi:10.1016/j.susc.2006.12.092

Cited by 22 publications

(41 citation statements)

References 46 publications

(80 reference statements)

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“…25 We examined both structures by DFT and found that neither of them represents a minimum on the potential energy surface but rather high-order saddle points. Hydroxyl groups recombine easily when the symmetry constraints are lifted and small displacements are made along an imaginary frequency mode, resulting in a structure with only one-quarter of the water monolayer dissociated.…”

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confidence: 99%

Water on the MgO(001) Surface: Surface Reconstruction and Ion Solvation

Ončák

Włodarczyk

Sauer

2015

J. Phys. Chem. Lett.

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The interaction of water with the MgO(001) surface under ambient conditions is investigated by density functional theory combined with statistical thermodynamics. For water loadings of more than one monolayer, we show that the standard structure model, a fully hydroxylated surface, needs to be revised. Reconstructed surfaces, involving hydrated/hydroxylated Mg(2+) ions above the surface, are more stable. These findings provide a consistent picture for surface hydroxylation between low and high water coverage that is in agreement with available XPS data.

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confidence: 99%

Water on the MgO(001) Surface: Surface Reconstruction and Ion Solvation

Ončák

Włodarczyk

Sauer

2015

J. Phys. Chem. Lett.

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“…More recently, MSINDO studies using cyclic cluster models have shown that partial dissociation of a water monolayer on MgO(100) was found to be more stable than molecular adsorption. [25][26][27] The corresponding model for NiO is shown in Figure 2 as NP mm 21 .…”

Section: The Hydrated Surface Modelsmentioning

confidence: 99%

MSINDO study of acid promoted dissolution of planar MgO and NiO surfaces

Simpson¹,

Bredow²,

Gerson³

2008

J Comput Chem

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Despite the structural similarity, MgO is fast dissolving in low pH solution, whereas NiO is slow dissolving under the same conditions. In addition, the planar MgO (100) surface immediately reconstructs to form pits and protrusions, whereas this behavior has not been observed with NiO (100). Our previous study, using the semiempirical self-consistent field molecular orbital (SCFMO) method MSINDO showed that it was possible for MgO dissolution but not NiO dissolution to occur via the migration of a metal-oxygen pair to an ex situ position. However, we have now found a more energetically favorable and realistic dissolution mechanism involving the dissociation of a water molecule (adsorbed on a metal site) prior to migration. Products from this dissociation (H and OH) weaken adjacent metal-oxygen bonds. Dissociation of a second adsorbed water molecule is required to complete the process. For both oxides, the energy barrier determined from the energy profile of the metal-oxygen pair migration was found to be lower than the activation energy of water dissociation at the planar surface as reported in previous study. This would suggest that the dissociation of water molecules at the planar surface is rate-determining in the surface restructuring step of dissolution. It was demonstrated that surface restructuring and dissolution of MgO is possible whereas highly improbable for NiO, in agreement with experimental observations.

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“…The accuracy of MSINDO has been documented. This parametrization was used in our previous studies 2,13–15 . The brucite structures were treated as cyclic clusters.…”

Section: Computational Detailsmentioning

confidence: 99%

“…This parametrization was used in our previous studies. 2,[13][14][15] The brucite structures were treated as cyclic clusters. The cyclic cluster model (CCM) 21 is implemented in MSINDO.…”

Section: Computational Detailsmentioning

confidence: 99%

“…12 We wish to address this question on a microscopic scale with quantum chemical calculations. In a previous work, we considered the surface structures of water on periclase, 13 the molecular dynamics of water interaction with periclase at 300 K, 14 and the formation of nuclei of brucite under the reaction of periclase with water. 15 In the present work, we complete these studies with a discussion of the bulk modulus and hydration pressure in this reaction.…”

Section: Introductionmentioning

confidence: 99%

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Cyclic Cluster Study on the Bulk Modulus and Hydration Pressure of Magnesia Expansion

Jug¹,

Heidberg²,

Bredow³

et al. 2008

Journal of the American Ceramic Society

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Cyclic cluster studies with the quantum chemical method MSINDO were performed to elucidate the key properties of brucite concerning the magnesia expansion. A model is presented that allows the calculation of the compressibility of brucite under hydrostatic pressure. In this way, the bulk modulus of brucite can be determined via the binding energy. The elastic constants, Poisson's ratios, volume compressibility, and finally the bulk modulus were calculated and compared with the experimental values. Except for the component Ka of the compressibility, there is good agreement with the experimental values. Based on the bulk modulus, an expression for the volume change of brucite under pressure is derived. The hydration pressure of the periclase reaction with water to form brucite is related to the partial water vapor pressure. In this way, the maximum hydration pressure was determined.

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Cyclic cluster study of water adsorption structures on the MgO(100) surface

Cited by 22 publications

References 46 publications

Water on the MgO(001) Surface: Surface Reconstruction and Ion Solvation

Water on the MgO(001) Surface: Surface Reconstruction and Ion Solvation

MSINDO study of acid promoted dissolution of planar MgO and NiO surfaces

Cyclic Cluster Study on the Bulk Modulus and Hydration Pressure of Magnesia Expansion

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