Papers by Pier Silvestrelli
No evidence of a metal-insulator transition in dense hot aluminum: A first-principles study
Physical Review B, 1999
ABSTRACT
Maximally localized Wannier functions for simulations with supercells of general symmetry
Physical Review B, 1999
The maximally localized Wannier function method, in the version specifically developed to study d... more The maximally localized Wannier function method, in the version specifically developed to study disordered and isolated systems with simple-cubic supercells, is generalized for applications with supercells of general symmetry. Analysis of the localized Wannier functions in the water molecule demonstrates the effectiveness of the new algorithm.
DFT Investigation of Oligothiophenes on a Si(001) Surface
The Journal of Physical Chemistry C, 2010
... Francesca Costanzo*, Elisabetta Venuti, Raffaele Guido Della Valle, and Aldo Brillante,. Dipa... more ... Francesca Costanzo*, Elisabetta Venuti, Raffaele Guido Della Valle, and Aldo Brillante,. Dipartimento di Chimica Fisica ed Inorganica and INSTM-UdR Bologna, Università di Bologna, viale Risorgimento 4, I-40137 Bologna, Italy. ...
Are There Immobilized Water Molecules around Hydrophobic Groups? Aqueous Solvation of Methanol from First Principles
The Journal of Physical Chemistry B, 2009
Structural, dynamical, bonding, and electronic properties of water molecules around a soluted met... more Structural, dynamical, bonding, and electronic properties of water molecules around a soluted methanol molecule are studied from first principles. The results are compatible with experiments and qualitatively support the conclusions of recent classical molecular dynamics simulations concerning the controversial issue on the presence of "immobilized" water molecules around hydrophobic groups: the hydrophobic solute slightly reduces the mobility of many surrounding water molecules rather than immobilizing just the few ones which are closest to the methyl group. By generating maximally localized Wannier functions, a detailed description of the polarization effects in both solute and solvent molecules is obtained, which better elucidates the solvation process.
Van der Waals Interactions in DFT Made Easy by Wannier Functions
Physical Review Letters, 2008
Ubiquitous van der Waals interactions between atoms and molecules are important for many molecula... more Ubiquitous van der Waals interactions between atoms and molecules are important for many molecular and solid structures. These systems are often studied from first principles using the density functional theory (DFT). However, the commonly used DFT functionals fail to capture the essence of van der Waals effects. Most attempts to correct for this problem have a basic semiempirical character, although computationally more expensive first principles schemes have been recently developed. We here describe a novel approach, based on the use of the maximally localized Wannier functions, that appears to be promising, being simple, efficient, accurate, and transferable (charge polarization effects are naturally included). The results of test applications to small molecules and bulk graphite are presented.
Chemistry - A European Journal, 2006
The structural, electronic and the bonding properties of the Sn-BEA are investigated by using the... more The structural, electronic and the bonding properties of the Sn-BEA are investigated by using the periodic density functional theory. Each of the 9 different T-sites in the BEA were substituted by the Sn atom and all the 9 geometries were completely optimized using the plane wave basis set in conjunction with the ultra-soft pseudopotential. On the basis of the structural and the electronic properties, it has been demonstrated that the substitution of the Sn atom in the BEA framework is an endothermic process and hence the incorporation of the Sn in the BEA is limited. The lowest unoccupied molecular orbitals (LUMO) energies have been used to characterize the Lewis acidity of each T-site. On the basis of the relative cohesive energy and the LUMO energy, T2 site is shown to be the most favorable site for the substitution of Sn atom in the BEA framework.
Erratum: van der Waals interactions in density functional theory using Wannier functions: Improved C 6 and C 3 coefficients by a different approach [Phys. Rev. B 85 , 073101 (2012)]
Physical Review B, 2013
ABSTRACT A different implementation is proposed for including van der Waals interactions in densi... more ABSTRACT A different implementation is proposed for including van der Waals interactions in density functional theory using the maximally localized Wannier functions. With respect to the previous DFT/vdW-WF method, the present DFT/vdW-WF2 approach, which is based on the simpler London expression and takes into account the intrafragment overlap of the localized Wannier functions, leads to a considerable improvement in the evaluation of the C6 van der Waals coefficients, as shown by the application to a set of selected dimers. Preliminary results on Ar on graphite and Ne on the Cu(111) metal surface also suggest that the C3 coefficients characterizing molecule-surfaces van der Waals interactions are better estimated with this scheme.
We study minimal surfaces in generic sub-Riemannian manifolds with sub-Riemannian structures of c... more We study minimal surfaces in generic sub-Riemannian manifolds with sub-Riemannian structures of co-rank one. These surfaces can be defined as the critical points of the so-called horizontal area functional associated to the canonical horizontal area form. We derive the intrinsic equation in the general case and then consider in greater detail 2-dimensional surfaces in contact manifolds of dimension 3. We show that in this case minimal surfaces are projections of a special class of 2-dimensional surfaces in the horizontal spherical bundle over the base manifold. Generic singularities of minimal surfaces turn out the singularities of this projection, and we give a complete local classification of them. We illustrate our results by examples in the Heisenberg group and the group of roto-translations.
PACS. 71.30+h -Metal-insulator transitions. PACS. 61.20Ja -Computer simulation. PACS. 65.50+m-The... more PACS. 71.30+h -Metal-insulator transitions. PACS. 61.20Ja -Computer simulation. PACS. 65.50+m-Thermodynamic properties and entropy.
We use the maximally-localized Wannier function method to study bonding properties in amorphous s... more We use the maximally-localized Wannier function method to study bonding properties in amorphous silicon. This study represents, to our knowledge, the first application of the Wannier-function analysis to a disordered system. Our results show that, in the presence of disorder, this method is extremely helpful in providing an unambiguous picture of the bond distribution. In particular, defect configurations can be studied and characterized with a novel degree of accuracy that was not available before.
Ab initio molecular dynamics simulation of laser melting of graphite
Journal of Applied Physics
The method of ab initio molecular dynamics, based on finite temperature density functional theory... more The method of ab initio molecular dynamics, based on finite temperature density functional theory, is used to simulate laser heating of crystal silicon. We have found that a high concentration of excited electrons dramatically weakens the covalent bond. As a result, the system ...
Dissociative chemisorption of methylsilane on the Si(100) surface
The Journal of Chemical Physics
ABSTRACT
The Journal of Chemical Physics
ABSTRACT
Adsorption of organic molecules on semiconductor surfaces from first principles: benzene and acetylene on Si(100)
ABSTRACT
Ab initio simulation of laser-induced transformations in fullerite
Physical Review B
ABSTRACT
High Energy Density Physics, 2014
We study the ratio of viscosity to entropy density in Yukawa one-component plasmas as a function ... more We study the ratio of viscosity to entropy density in Yukawa one-component plasmas as a function of coupling parameter at fixed screening, and in realistic warm dense matter models as a function of temperature at fixed density. In these two situations, the ratio is minimized for values of the coupling parameters that depend on screening, and for temperatures that in turn depend on density and material. In this context, we also examine Rosenfeld arguments relating transport coefficients to excess reduced entropy for Yukawa one-component plasmas. For these cases we show that this ratio is always above the lower-bound conjecture derived from string theory ideas.
Adsorption of C-based molecules at the Si surface: the initial stages of SiC growth, from ab-initio simulations
We review some recent results on the adsorption mechanisms of C atoms and molecules at the Si(001... more We review some recent results on the adsorption mechanisms of C atoms and molecules at the Si(001) and Si(111) surfaces via ab-initio molecular dynamic simulations at finite temperature. Our calculations show that for all the adsorbed species, and substrate orientations, at low temperatures the preferred adsorption sites stay at the surface: This is accomplished through the formation of Si-C bonds
Van der Waals interactions at surfaces by DFT using Wannier functions
The z axis magnetization of a two dimensional electron gas with contact repulsive interaction and... more The z axis magnetization of a two dimensional electron gas with contact repulsive interaction and in presence of a Rashba potential is computed by means of quantum field theory at second order. A striking effect of the pure Rashba interaction is that of hindering spin alignment along the z direction. Evidence of transition at critical repulsive interaction coupling constant is still found. The degree of magnetization, however, shows a clear dependence on the spin-orbit interaction strength. Furthermore, the transition to magnetized state appears to be smoothed by the presence of the Rashba interaction.
Uploads
Papers by Pier Silvestrelli