Publications

V is the only element in the periodic table that forms a complete solid solution with Cr and thus is particularly important in alloying strategy to ductilize Cr. This study combines first-principles density functional theory calculations and experiments to investigate the phase stability and...

The site occupancy of the various oxidation state of palladium supported on mesostructured porous aluminosilica of Al-MCM-41 type was studied combining density functional theory (DFT), FTIR, and Raman investigations. The study focuses on the usual +2 oxidation state highly dispersed during...

The determination of the nature and structure of surface sites after chemical modification of large surface area oxides such as silica is a key point for many applications and challenging from a spectroscopic point of view. This has been, for instance, a long-standing problem for silica reacted...

The mechanism of Li⁺ transport through the solid electrolyte interphase (SEI), a passivating film on electrode surfaces, has never been clearly elucidated despite its overwhelming importance to Li-ion battery operation and lifetime. The present paper develops a multiscale theoretical methodology...

We discuss the structural details and the ordering of hydrogen in LaHx for 2⩽x⩽3. To this end, we combine first-principles calculations with the cluster-expansion method. This approach allows us to follow the H occupation of the interstitial sites within the face-centered cubic matrix of La...

New calculations for vanadium dioxide, one of the most controversially discussed materials for decades, reveal that band theory as based on density functional theory is well capable of correctly describing the electronic and magnetic properties of the metallic as well as both the insulating M1...

KSi silicide can absorb hydrogen to directly form the ternary KSiH₃ hydride. The full structure of α-KSiD₃, which has been solved by using neutron powder diffraction (NPD), shows an unusually short Si-D lengths of 1.47 Å. Through a combination of density functional theory (DFT) calculations and...

The interaction energies (IEs) of H₂ and various organic ligands have been computed using coupled-cluster method with singles, doubles, and noniterative triples (CCSD(T)) at the complete basis set (CBS) limit. The density fitting-density functional theory-symmetry adapted perturbation theory (DF...

The process of grafting H₃PMo₁₂O₄₀ onto silica surfaces is studied using periodic density functional theory methods. For surfaces with a high hydroxyl coverage, the hydroxyl groups are consumed by the polyoxometalate protons, resulting in water formation and the creation of a covalent bond...

La modélisation moléculaire permet aujourd'hui de simuler les matériaux ou les fluides à l'échelle du nanomètre, voire de l'ångström, en s'appuyant sur les lois les plus fondamentales de la mécanique quantique ou de la mécanique statistique. Cette discipline de la chimie physique bénéficie des...

Results from first-principles investigations of the energetical, structural, electronic, and vibrational properties of model structures probing the metal-rich region of the lanthanum-hydrogen system, i.e., the region of the solid solution of hydrogen in lanthanum, are presented. We have studied...

Atomic modeling was conducted to investigate the origin of S interactions with Pd alloy H selective membrane candidates selected from the Pd–Cu, Pd–Ag, and Pd–Au binary systems, as well as their constitutive metals. The electronic characteristics of these alloy/metal systems played a more...

The increase in oxygen binding energy was previously proposed to account for the lower oxygen reduction activity of a Pt monolayer supported on Au(111) single crystal than that on Pd(111) and pure Pt(111) surfaces. This single-crystal based understanding, however, cannot explain the new finding...

An efficient procedure for normal-mode analysis of extended systems, such as zeolites, is developed and illustrated for the physisorption and chemisorption of n-octane and isobutene in H-ZSM-22 and H-FAU using periodic DFT calculations employing the Vienna Ab Initio Simulation Package....

The deleterious low-temperature tetragonal phases in prototypical Pt-based superalloys have variously been reported as taking the tI16-U₃Si (DOc), tI16-Ir₃Si (DOc′) and tP16-Pt₃Ga structure-types in contrast to the high-temperature cubic cP4-Cu₃Au (L12) phase. We have investigated the relative...

Density functional theory (DFT) is used to reveal that the polycrystalline Young’s modulus ͑ E of graphite triples as it is lithiated to LiC₆. This behavior is captured in a linear relationship between E and lithium concentration suitable for continuum-scale models aimed at predicting...

Self-diffusion coefficients for hcp Mg and Zn have been calculated from first-principles as a function of temperature, within the generalized gradient and local density approximations. The climbing image nudged elastic band (CI-NEB) method has been used to provide minimum energy pathways and...

In this paper we have applied first-principle density-functional theory to calculate some of the interesting roles played by vacancies in material properties, such as magnetic properties and complex formation. We use as examples our recent results on vacancies in group III-V semiconductors like...

The gamma surfaces in the pyramidal I {1 −1 0 1} and II {1 1−2 2} planes for hexagonal close packed Mg have been calculated using two embedded-atom-method potentials and by ab initio methods, and reasonable agreement is obtained for key stacking fault energies. Screw and edge 〈c + a〉 dislocation...

We present lattice constants, bulk moduli, and atomization energies of solids using the correlation energy evaluated within the adiabatic connection fluctuation-dissipation framework and applying the random-phase approximation. Recently, we have shown [Phys. Rev. Lett. 103 056401 (2009...

This paper reports an overview of recent DFT studies on the atomic scale characterization of Co(Ni)MoS active phases used in selective hydrodesulfurization (HDS) catalysis. A peculiar attention is paid to the effect of the sulfo-reductive reaction conditions on the stability and nature of the...

The adiabatic-connection fluctuation-dissipation theorem suggests that the correlation energy in the random phase approximation is a suitable complement to exact exchange. We show that lattice constants, bulk moduli, and atomization energies of solids evaluated using this approximation are in...

The temperature-dependent diffusion coefficients of interstitial hydrogen, deuterium, and tritium in nickel are computed using transition state theory. The coefficient of thermal expansion, the enthalpy and entropy of activation, and the pre-exponential factor of the diffusion coefficient are...

During the past decade, computer simulations based on a quantum-mechanical description of the interactions between electrons and between electrons and atomic nuclei have developed an increasingly important impact on solid-state physics and chemistry and on materials science—promoting not only a...

Skutterudite based materials are important for thermoelectric applications. In order to be able to tune the thermoelectric properties, it is necessary to understand the mechanism of thermal conductivity, which, in turn, is strongly influenced by the lattice dynamics. The lattice dynamics of the...

The structural, electronic, and phonon properties of the cubic and tetragonal phase of SrTiO₃ and BaTiO₃ are studied from ab initio. The calculations are performed in the projector augmented wave density-functional theory framework using the local density approximation, gradient corrected...

Structural and electronic properties of the α- and γ-phases of cerium sesquisulfide, Ce₂S₃, are examined by first-principles calculations using the GGA+U extension of density functional theory. The strongly correlated f-electrons of Ce are described by a Hubbard-type on-site Coulomb repulsion...

We present first-principles calculations for the fcc noble gas solids Ne, Ar, and Kr applying the adiabatic connection fluctuation-dissipation theorem (ACFDT) to evaluate the correlation energy. The ACFDT allows us to describe long-range correlation effects including London dispersion or van der...

First-principles calculations based on hybrid Hartree-Fock density functionals provide a clear picture of the defect energetics and electronic structure in ZnO. Among the donorlike defects, the oxygen vacancy and hydrogen impurity, which are deep and shallow donors, respectively, are likely to...

We present a detailed study of the adsorption of CO on Cu, Rh, and Pt (111) surfaces in top and hollow sites. The study has been performed using the local density approximation, the gradient corrected functional PBE, and the hybrid Hartree-Fock density functionals PBE0 and HSE03 within the...

Combining experiments and ab initio models we report on SrPt₄Ge₁₂ and BaPt₄Ge₁₂ as members of a novel class of superconducting skutterudites, where Sr or Ba atoms stabilize a framework entirely formed by Ge atoms. Below Tc=5.35 and 5.10 K forBaPt₄Ge₁₂ and SrPt₄Ge₁₂, respectively, electron-phonon...

Self-consistent GW calculations, maintaining only the quasiparticle part of the Green's function G, are reported for a wide class of materials, including small gap semiconductors and large gap insulators. We show that the inclusion of the attractive electron-hole interaction via an effective...

First-principles modeling, experimental, and thermodynamic methodologies were integrated to facilitate a fundamentally guided investigation of quaternary complex hydride compounds within the bialkali Na−Li−Al−H hydrogen storage system. The integrated approach has broad utility for the discovery...

By an ab initio density functional approach, structural, magnetic, vibrational, and thermodynamic properties of HfMn₂ were studied. These properties were derived for the C14, C15, and C36 crystal structures, revealing a close energetical competition between the ferromagnetically ordered phases...

Based on density-functional calculations, we propose that ZrMn₂ is a polymorphic material. We predict that at low temperatures the cubic C15, and the hexagonal C14 and C36 structures of the Laves phase compound ZrMn₂ are nearly equally stable within 0.3 kJ mol⁻¹ or 30 K. This degeneracy occurs...

The B3LYP hybrid functional has shown to successfully predict a wide range of molecular properties. For periodic systems, however, the failure to attain the exact homogeneous electron gas limit as well as the semiempirical construction turns out to be a major drawback of the functional. We...

In this work we derive closed expressions for the head of the frequency-dependent microscopic polarizability matrix in the projector-augmented wave (PAW) methodology. Contrary to previous applications, the lon- gitudinal expression is utilized, resulting in dielectric properties that are...

The present work extends previous work on modeling the effect of a sinusoidal interface pattern on interfacial toughening between identical materials by incorporating both elastic-perfectly plastic and elastic-power-law-hardening models. The materials are assumed to be bonded by an...

Present local and semilocal functionals show significant errors, for instance, in the energetics of small molecules and in the description of band gaps. One possible solution to these problems is the introduction of exact exchange and hybrid functionals. A plane-wave-based algorithm was...

A density functional theory investigation of the recently identified hydrogen storage reaction LiNH₂ + LiH ↔ Li₂NH + H₂ is described. The electronic structure and enthalpy of formation ΔH of each constituent are calculated in both the generalized gradient approximation (GGA) and the local density...

The simulation of vibrational properties and finite temperature effects based on ab initio calculation of phonons within the direct approach is discussed.

Using a first-principles methodology, we investigated the effect of diamond surface termination on the work of separation ( W sep) , interface geometry, bond character, and adhesive transfer of three Al/diamond interfaces, viz., Al(111)/C(111)-1×1, Al(111)/C(111)-2×1 and Al(111)/C(111)-1×1:H....

Ab initio calculations of the basic properties of solids have advanced significantly, and it is now possible to simply access a crystal structure database, and from the given constituent atoms and their positions, calculate reasonably accurate values for elastic constants and thermomechanical...

Band structures and dielectric functions are calculated using density-functional theory and local-density approximation for three β-cristobalite modifications of SiO₂ with space-group symmetries Fd3m, I4¯2d, and P213. Quasiparticle corrections for the Kohn-Sham eigenvalues are determined in a GW...

We present a detailed ab initio investigation of the stability, the structural, electronic, and magnetic properties of the (0001) surfaces of hematite (Fe₂O₃) and chromia or eskolaite (Cr₂O₃). Strong electron correlation effects not included in a density-functional description are described by a...

Atomistic modeling was used to investigate the effects of impurity elements on the metallurgy, irradiation embrittlement, and environmentally assisted cracking of nickel-base alloys. Calculations were performed via ab initio atomistic modeling on a nickel Σƒ5 {001} twist grain boundary. A...

The crystallographic structure of switchable mirror material YD₃ is still under debate. Aiming at a final structure assessment, currently considered structure models of P-3c1 , P63cm and P63 symmetry are studied by means of ab initio methods. The relative stability of these candidate structures...

The timely integration of crystal structure databases, such as CRYSTMET, ICSD etc., with quantum software, like VASP, OresteS, ElectrA etc., allows ab initio cell and structure optimization on existing pure-phase compounds to be performed seamlessly with just a few mouse clicks. Application to...

Ab-initio stiffness values were computed in an automated way for two trigonal reference materials: dextro low quartz and calcite with respective space groups P3₂21 and R-3c. Both were computed in their IRE settings, namely with r faces indexed {10-11} for right-quartz and with obverse setting of...

Accurate band structures of binary semiconductors AB (A = Al, Ga, In and B = P, As, Sb) and selected ternary III–V semiconductors were calculated using an all-electron screened exchange approach within the full potential linearized augmented plane-wave method. Fundamental band gaps and Γ–L and Γ...

Grand canonical ensemble Monte Carlo simulations of the adsorption properties of several model faujasite zeolites were performed using the statistical bias method. The results enable a better understanding of the effect of cation exchange in the selective adsorption of binary mixtures of para-...

A symmetry-general scheme for the simultaneous least-squares extraction of the elastic coefficients and of the residual strain components from ab initio total energy calculations on crystal structure models of materials is proposed. It is quite efficient and avoids error propagation. An...

We compare hybrid Hartree−Fock density-functional theory to ab initio approaches for locating saddle point geometries and calculating barrier heights on a Born−Oppenhiemer potential energy surface. We located reactant, product, and saddle point stationary points for 22 reactions by the MP2 and...

Quasiparticle electronic band structures for ternary InGaAs and InGaSb systems, modeled by a luzonite structure, have been obtained using the screened-exchange local-density approximation approach. We focus our attention on energy transitions relevant for the electron-hole pair lifetime and, in...

Periodic density functional calculations on zeolite Na-MAP are presented. These calculations used a preliminary model obtained from X-ray powder diffraction as starting point and fully optimized the atom positions within the unit cell. It is shown that the structure obtained in the calculation...

We have employed Monte Carlo simulation in the NPT ensemble to determine the molar volume and the compressibility factor of naturally occurring hydrocarbon gas mixtures. The simulation results were compared to experimental data as well as to predictions based on both the Peng–Robinson and AGA 8...

The properties of p-xylene and m-xylene adsorbed in NaY and KY faujasites have been studied by grand canonical Monte Carlo simulation. Biased particle insertions and deletions were implemented to allow the computation of equilibrium adsorption isotherms of such complex systems. This work is...