Publisher's Note: “Density, structure, and dynamics of water: The effect of van der Waals interactions” [J. Chem. Phys. 134, 024516 (2011)]

Wang, Jue; Román-Pérez, Guillermo; Soler, José M.; Artacho, Emilio; Fernández-Serra, M.-V.

doi:10.1063/1.3553376

Cited by 84 publications

(156 citation statements)

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“…10 It is worth mentioning that vdW-PBE has been employed to successfully reproduce structural properties of liquid water. 20 In this case, the vdW-PBE functional led to a better description of the radial distribution function compared to vdW-DF, due to the underestimation of H-bond interaction and a consequent overestimation of the O−O distance by revPBE.…”

Section: ■ Computational Detailsmentioning

confidence: 90%

CO₂ Capture by Metal–Organic Frameworks with van der Waals Density Functionals

2012

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We use density functional theory calculations with van der Waals corrections to study the role of dispersive interactions on the structure and binding of CO 2 within two distinct metal−organic frameworks (MOFs): Mg-MOF74 and Ca-BTT. For both classes of MOFs, we report calculations with standard gradient-corrected (PBE) and five van der Waals density functionals (vdW-DFs), also comparing with semiempirical pairwise corrections. The vdW-DFs explored here yield a large spread in CO 2 −MOF binding energies, about 50% (around 20 kJ/ mol), depending on the choice of exchange functional, which is significantly larger than our computed zero-point energies and thermal contributions (around 5 kJ/mol). However, two specific vdW-DFs result in excellent agreement with experiments within a few kilojoules per mole, at a reduced computational cost compared to quantum chemistry or many-body approaches. For Mg-MOF74, PBE underestimates adsorption enthalpies by about 50%, but enthalpies computed with vdW-DF, PBE+D2, and vdW-DF2 (40.5, 38.5, and 37.4 kJ/mol, respectively) compare extremely well with the experimental value of 40 kJ/mol. vdW-DF and vdW-DF2 CO 2 −MOF bond lengths are in the best agreement with experiments, while vdW-C09 x results in the best agreement with lattice parameters. On the basis of the similar behavior of the reduced density gradients around CO 2 for the two MOFs studied, comparable results can be expected for CO 2 adsorption in BTT-type MOFs. Our work demonstrates for this broad class of molecular adsorbate-periodic MOF systems that parameter-free and computationally efficient vdW-DF and vdW-DF2 approaches can predict adsorption enthalpies with chemical accuracy. ■ INTRODUCTIONMetal−organic frameworks (MOFs) are a broad class of threedimensional nanoporous materials that have attracted much attention during the past decade for CO 2 capture from flue gas. 1−6 MOFs consist of metal centers joined by organic molecular "linkers"; there are many possibilities for cation/ linker combinations, and thousands of different MOFs have already been synthesized. 3,5 Understanding mechanisms for CO 2 binding within these frameworks is a fundamental step toward the design of new materials for carbon capture.In order to explore and predict new materials that efficiently capture CO 2 , an accurate quantitative description of both its adsorption energy and geometry is needed. Whereas quantum chemistry methods, such as HF/MP2 or CCSD(T), scale unfavorably with the number of basis functions (N 5 and N 7 ) and are primarily restricted to cluster calculations, density functional theory (DFT) is a very promising framework for studying the mechanism of interaction between CO 2 and extended MOFs. Although DFT is a many-particle framework that includes, in principle, fully nonlocal interactions, its common approximations, such as the local density approximation (LDA) and the generalized gradient approximation (GGA), neglect attractive long-range contributions to van der Waals interactions, so-called London dispersion intera...

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Section: ■ Computational Detailsmentioning

confidence: 90%

CO₂ Capture by Metal–Organic Frameworks with van der Waals Density Functionals

2012

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“…We find that the PBE functional gives an average density for liquid water of ∼0.87 g/cm 3 underestimating the experimental value by about 13%, in very good agreement with previous theoretical studies. 10,22 In contrast, the explicit introduction of van der Waals interactions, described by the rVV10 functional with the parameter b set to its original value of 6.3, causes an overestimation of the equilibrium density. We obtain a value of ∼1.10 g/cm 3 , about 10% higher than the experimental value.…”

Section: A Equilibrium Densitymentioning

confidence: 99%

“…More recently, several strategies for including van der Waals interactions within density functional simulation schemes have been proposed leading to an improved description of the structural and dynamical properties of liquid water. 10,[21][22][23] In particular, Schmidt et al performed molecular dynamics simulations of liquid water in the isobaric-isothermal ensemble (N pT ). 10 In N pT simulations, the supercell parameters are free to adjust during the evolution allowing the system to reach its equilibrium density at a fixed pressure without imposing additional constraints.…”

Section: Introductionmentioning

confidence: 99%

Isobaric first-principles molecular dynamics of liquid water with nonlocal van der Waals interactions

Miceli

Gironcoli

Pasquarello

2015

The Journal of Chemical Physics

114

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We investigate the structural properties of liquid water at near ambient conditions using first-principles molecular dynamics simulations based on a semilocal density functional augmented with nonlocal van der Waals interactions. The adopted scheme offers the advantage of simulating liquid water at essentially the same computational cost of standard semilocal functionals. Applied to the water dimer and to ice I h , we find that the hydrogen-bond energy is only slightly enhanced compared to a standard semilocal functional. We simulate liquid water through molecular dynamics in the N pH statistical ensemble allowing for fluctuations of the system density. The structure of the liquid departs from that found with a semilocal functional leading to more compact structural arrangements. This indicates that the directionality of the hydrogenbond interaction has a diminished role as compared to the overall attractions, as expected when dispersion interactions are accounted for. This is substantiated through a detailed analysis comprising the study of the partial radial distribution functions, various local order indices, the hydrogen-bond network, and the selfdiffusion coefficient. The explicit treatment of the van der Waals interactions leads to an overall improved description of liquid water.

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“…V (B) − 1, is the relative isotope shift for the exchange of isotope A by B. The exchange and correlation (XC) functionals are: PBE [33], vdW-DF PBE [27,35], revPBE [34], and vdW-DF revPBE [35]. The force fields (FF) are q-TIP4P/F [2] and TTM3-F [23] V cla is the volume for classical nuclei.…”

Section: Pdosmentioning

confidence: 99%

“…We use a basis of triple-ζ polarized orbitals, a longer and improved version of the basis set used in Ref. 27. Given the precision needed to obtain accurate Grüneisen parameters, which involve numerical second derivatives of the forces, we have used highly converged grids for realspace and k-sampling integrations.…”

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confidence: 99%

Anomalous Nuclear Quantum Effects in Ice

et al. 2012

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One striking anomaly of water ice has been largely neglected and never explained. Replacing hydrogen ( 1 H) by deuterium ( 2 H) causes ice to expand, whereas the "normal" isotope effect is volume contraction with increased mass. Furthermore, the anomaly increases with temperature T , even though a normal isotope shift should decrease with T and vanish when T is high enough to use classical nuclear motions. In this study, we show that these effects are very well described by ab initio density functional theory. Our theoretical modeling explains these anomalies, and allows us to predict and to experimentally confirm a counter effect, namely that replacement of 16 =0 [15]. This "normal" isotope effect corresponds to a ∼12% zero-point expansion of 20 Ne relative to a hypothetical "classical" or "frozen" lattice [16,17]. Since H 2 O and Ne have similar molecular masses, one might expect similar effects. However, the volume of H 2 O at T = 0 is ∼0.1% smaller than that of D 2 O [12,13]. It has rarely been mentioned in the literature that this is opposite to the usual behavior, and no explanation has been offered.In this paper, we explain this effect as an interesting coupling between quantum nuclear motion and hydrogen bonding, that may be relevant also to the structure of liquid water. Our analysis shows that, despite the anomalous isotope effect, quantum ice actually has a volume 1% larger than it would have with classical nuclei. The effects are smaller than in Ne mostly because of delicate cancellations. We exploit these cancellations to make critical comparisons of: (i) quasiharmonic theory versus fully anharmonic path-integral molecular dynamics (PIMD); (ii) ab initio forces versus flexible and polarizable empirical force fields (EFF); and (iii) various flavors of ab initio density-functional theory (DFT) exchange and correlation (XC) density functionals (DF) with and without inclusion of van der Waals (vdW) interactions. We find: (i) quasiharmonic theory is satisfactory for this problem; (ii) present state of the art EFFs are not good enough to describe nuclear quantum effects in water; and (iii) all the DFs considered describe qualitatively the anomalous effects, although some versions perform better than others.Within the volume-dependent quasiharmonic approximation (QHA), the equilibrium volume V (T ) is obtained by minimizing at each T the Helmholtz free energy F (V, T ) [18,19]:where E 0 (V ) is the energy for classical (T = 0 or frozen) nuclei, at the relaxed atomic coordinates for each volume. ω k are the phonon frequencies, with k combining the branch index and the phonon wave vector within the Brillouin zone. Their volume dependence is linearized as:whereis the Grüneisen parameter of the mode, and V 0 is the equilibrium volume of E 0 (V ). ω k (V 0 ) and γ k (V 0 ) are obtained by diagonalizing the dynamical matrix, computed by finite differences from the atomic forces in a (3 × 3 × 3) supercell, at two volumes slightly below and above V 0 . As shown in the supplementary information [20] (SI), this li...

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Publisher's Note: “Density, structure, and dynamics of water: The effect of van der Waals interactions” [J. Chem. Phys. 134, 024516 (2011)]

Cited by 84 publications

References 0 publications

CO₂ Capture by Metal–Organic Frameworks with van der Waals Density Functionals

CO₂ Capture by Metal–Organic Frameworks with van der Waals Density Functionals

Isobaric first-principles molecular dynamics of liquid water with nonlocal van der Waals interactions

Anomalous Nuclear Quantum Effects in Ice

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Publisher's Note: “Density, structure, and dynamics of water: The effect of van der Waals interactions” [J. Chem. Phys. 134, 024516 (2011)]

Cited by 84 publications

References 0 publications

CO2 Capture by Metal–Organic Frameworks with van der Waals Density Functionals

CO2 Capture by Metal–Organic Frameworks with van der Waals Density Functionals

Isobaric first-principles molecular dynamics of liquid water with nonlocal van der Waals interactions

Anomalous Nuclear Quantum Effects in Ice

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Product

Resources

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CO₂ Capture by Metal–Organic Frameworks with van der Waals Density Functionals

CO₂ Capture by Metal–Organic Frameworks with van der Waals Density Functionals