0000000000007118

AUTHOR

Simona Ispas

showing 3 related works from this author

Amorphous silica modeled with truncated and screened Coulomb interactions: A molecular dynamics simulation study

2007

We show that finite-range alternatives to the standard long-range BKS pair potential for silica might be used in molecular dynamics simulations. We study two such models that can be efficiently simulated since no Ewald summation is required. We first consider the Wolf method, where the Coulomb interactions are truncated at a cutoff distance r_c such that the requirement of charge neutrality holds. Various static and dynamic quantities are computed and compared to results from simulations using Ewald summations. We find very good agreement for r_c ~ 10 Angstroms. For lower values of r_c, the long--range structure is affected which is accompanied by a slight acceleration of dynamic properties…

PhysicsStatistical Mechanics (cond-mat.stat-mech)010304 chemical physicsCoulomb interactionsStructure (category theory)FOS: Physical sciencesGeneral Physics and Astronomymolecular dynamics computer simulationYukawa interactionEwald sums01 natural sciencesMolecular physicsEwald summationAccelerationMolecular dynamicssilica0103 physical sciencesCoulombCutoffPhysical and Theoretical Chemistry[PHYS.COND.CM-SM]Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech]010306 general physicsPair potentialCondensed Matter - Statistical Mechanics
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New fitting scheme to obtain effective potential from Car-Parrinello molecular dynamics simulations: Application to silica

2008

A fitting scheme is proposed to obtain effective potentials from Car-Parrinello molecular dynamics (CPMD) simulations. It is used to parameterize a new pair potential for silica. MD simulations with this new potential are done to determine structural and dynamic properties and to compare these properties to those obtained from CPMD and a MD simulation using the so-called BKS potential. The new potential reproduces accurately the liquid structure generated by the CPMD trajectories, the experimental activation energies for the self-diffusion constants and the experimental density of amorphous silica. Also lattice parameters and elastic constants of alpha-quartz are well-reproduced, showing th…

Car–Parrinello molecular dynamicsMaterials sciencemolecular dynamics calculations (Car-Parrinello) and other numerical simulationsTransferabilityGeneral Physics and AstronomyFOS: Physical sciences02 engineering and technologyglasses01 natural sciencesMolecular physicsMolecular dynamicsLattice (order)0103 physical sciences[PHYS.COND.CM-DS-NN]Physics [physics]/Condensed Matter [cond-mat]/Disordered Systems and Neural Networks [cond-mat.dis-nn]010306 general physicsdensity functional theoryCondensed Matter - Materials Sciencegradient and other correctionsMaterials Science (cond-mat.mtrl-sci)Disordered Systems and Neural Networks (cond-mat.dis-nn)computer simulation of liquid structureCondensed Matter - Disordered Systems and Neural Networks021001 nanoscience & nanotechnologylocal density approximation[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]Amorphous silica0210 nano-technologyPair potential
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Comparative classical and ab initio Molecular Dynamics study of molten and glassy germanium dioxide

2008

A Molecular Dynamics (MD) study of static and dynamic properties of molten and glassy germanium dioxide is presented. The interactions between the atoms are modelled by the classical pair potential proposed by Oeffner and Elliott (OE) [Oeffner R D and Elliott S R 1998, Phys. Rev. B, 58, 14791]. We compare our results to experiments and previous simulations. In addition, an ab initio method, the so-called Car-Parrinello Molecular Dynamics (CPMD), is applied to check the accuracy of the structural properties, as obtained by the classical MD simulations with the OE potential. As in a similar study for SiO2, the structure predicted by CPMD is only slightly softer than that resulting from the cl…

Condensed Matter - Materials ScienceGermanium dioxideCar–Parrinello molecular dynamicsMaterials scienceDynamic structure factorRelaxation (NMR)Ab initioMaterials Science (cond-mat.mtrl-sci)FOS: Physical sciencesThermodynamicsDisordered Systems and Neural Networks (cond-mat.dis-nn)Condensed Matter - Disordered Systems and Neural NetworksCondensed Matter Physicschemistry.chemical_compoundMolecular dynamicsgermaniamolecular dynamics simulationchemistryAb initio quantum chemistry methodsGeneral Materials SciencePair potential
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