Sergio Alexis Paz

Sergio Alexis Paz
National Scientific and Technical Research Council | conicet · INFIQC Instituto de Investigaciones en Físico Química de Córdoba

PhD in Chemistry

About

32
Publications
3,788
Reads
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193
Citations
Additional affiliations
February 2014 - present
Drexel University
Position
  • PostDoc Position
Education
November 2008 - December 2013
National University of Cordoba
Field of study
  • Simulation of nanoscale phenomena through different computational methods
January 2004 - November 2008
National University of Córdoba
Field of study
  • Química

Publications

Publications (32)
Preprint
In this work, we developed a computational model of lithium deposition on planar electrodes. With this model, we simulated several chronoamperometry experiments considering different deposition probabilities, i.e. cell overpotentials. Since the planar geometry induces an ion concentration gradient profile that continues to evolve toward the bulk el...
Article
Silicon anodes hold great promise for next-generation Li-ion batteries. The main obstacle to exploiting their high performance is the challenge of linking experimental observations to atomic structures due to the amorphous nature of Li-Si alloys. We unveil the atomistic-scale structures of amorphous Li-Si using our recently developed density functi...
Preprint
Full-text available
We present a new approach to studying nanoparticle collisions using Density Functional based Tight Binding (DFTB). A novel DFTB parameterisation has been developed to study the collision process of Sn and Si nanoparticles (NPs) using Molecular Dynamics (MD). While bulk structures were used as training sets, we show that our model is able to accurat...
Preprint
Full-text available
Silicon anodes hold great promise for next-generation Li-ion batteries. The main obstacle to exploiting their high performance is the challenge of linking experimental observations to atomic structures due to the amorphous nature of Li-Si alloys. We unveil the atomistic-scale structures of amorphous Li-Si using our recently developed density functi...
Article
The recent determination of cryo-EM structures of voltage-gated sodium (Nav) channels has revealed many details of these proteins. However, knowledge of ionic permeation through the Nav pore remains limited. In this work, we performed atomistic molecular dynamics (MD) simulations to study the structural features of various neuronal Nav channels bas...
Article
The predictive power of molecular dynamic simulations is mainly restricted by the time scale and model accuracy. Many systems of current relevance are of such complexity that they require addressing both issues simultaneously. This is the case of silicon electrodes in Li-ion batteries, where different LixSi alloys are formed during charge/discharge...
Preprint
Full-text available
The predictive power of molecular dynamic simulations is mainly restricted by the time scale and model accuracy. Many systems of current relevance are of such complexity that requires addressing both issues simultaneously. This is the case of silicon electrodes in Li-ion batteries, where different Li$_x$Si alloys are formed during charge/discharge...
Preprint
Full-text available
The recent determination of cryo-EM structures of voltage-gated sodium (Nav)channels has revealed many details of these proteins. However, knowledge of ionic permeation through the Nav pore remains limited. In this work, we performed atomistic molecular dynamics simulations to study the structural features of various neuronal Nav channels based on...
Article
Full-text available
Screening already approved drugs for activity against a novel pathogen can be an important part of global rapid-response strategies in pandemics. Such high-throughput repurposing screens have already identified several existing drugs with potential to combat SARS-CoV-2. However, moving these hits forward for possible development into drugs specific...
Article
Full-text available
Motivated by the abundant experimental work in the area of Li-ion batteries, in the present work we characterize via computer simulations the structure of Si-Li amorphous alloys in a wide range of compositions. Using a reactive force field we propose a novel accelerated exploration of local minima to obtain amorphous structures close to equilibrium...
Preprint
Full-text available
Screening already approved drugs for activity against a novel pathogen can be an important part of global rapid-response strategies in pandemics. Such high-throughput repurposing screens have already identified several existing drugs with potential to combat SARS-CoV-2. However, moving these hits forward for possible development into drugs specific...
Preprint
Screening already approved drugs for activity against a novel pathogen can be an important part of global rapid-response strategies in pandemics. Such high-throughput repurposing screens have already identified several existing drugs with potential to combat SARS-CoV-2. However, moving these hits forward for possible development into drugs specific...
Article
We introduce a two-dimensional version of the method called on-the-fly free energy parameterization (OTFP), to reconstruct free-energy surfaces using Molecular Dynamics simulations, which we name OTFP-2D. We first test the new method by reconstructing the well-known dihedral angles free energy surface of solvated alanine dipeptide. Then, we use it...
Article
Full-text available
In this work, we study the influence of hidden barriers on the convergence behavior of three free-energy calculation methods: well-tempered metadynamics (WTMD), adaptive-biasing forces (ABF), and on-the-fly parameterization (OTFP). We construct a simple two-dimensional potential-energy surfaces (PES) that allows for an exact analytical result for t...
Article
The coalescence process of two nanoparticles to yield a core-shell structure is analyzed by a Well-Tempered Metadynamics procedure. This methodology shows to be useful to understand the present phenomenon in terms of two collective variables: the distance between the center of mass of the coalescing particles and the gyration radius of the resultin...
Article
Full-text available
We study the thermodynamic stability of the native state of the human prion protein using a new free-energy method, replica-exchange on-the-fly paramaterization. This method is designed to overcome hidden-variable sampling limitations to yield nearly error-free free-energy profiles along a conformational coordinate. We confirm that all four (M129V,...
Article
On-the-fly free-energy parametrization is a new collective variable biasing approach akin to metadynamics with one important distinction: rather than acquiring an accelerated distribution via a history-dependent bias potential, sampling on this distribution is achieved from the beginning of the simulation using temperature-accelerated molecular dyn...
Article
BaLaCuSbO6 double perovskite has been successfully synthesized by solid state reaction in air atmosphere. Its structure was refined using powder neutron diffraction in the monoclinic space group I 2/m with a 4% antisite disorder on the B cations. Magnetic measurements give signs of 2D-antiferromagnetic behaviour with TN around 64 K. The Jahn-Teller...
Article
A procedure usually applied to construct free energy surfaces for a system at equilibrium is found here useful for obtain information on a non-equilibrium process. The joint probability of observing collective variables from a swarm of irreversible molecular dynamic trajectories is analyzed. This straightforward procedure can supply detailed mechan...
Data
Conductance experiments on single molecular junctions are pushing the computational field towards new challenges involving conductance calculations along a large collection of molecular conformations. To tackle this problem, a combination of accelerated dynamics (to enhance sampling) and non-equilibrium Green functions (for conductance computation)...
Article
Accelerated molecular dynamics and quantum conductance calculations are employed to shed light onto the electrochemical properties of the Au|1,8-octanedithiol|Au junction. Widely different contact geometries with varying degrees of roughness are examined. Strikingly, the two extreme situations considered in this work, tip-tip and tip-perfect surfac...
Article
An accelerated dynamics scheme is employed to sample the configurational space of a system consisting of an alkanedithiol molecule confined to the gap between a metal tip and a perfect metal surface. With this information and by means of nonequilibrium green functions techniques (NEGF), conductance calculations are performed. The present results sh...
Article
Full-text available
Results of dynamical simulations of collision-induced formation and properties of bimetallic nanoparticles are presented and analyzed. The analysis includes the effects of the collision energy and the impact parameter. For nonzero impact parameters, the formed (in many cases Janus-type) nanoparticles are rotating. The energy of the rotating nanopar...
Conference Paper
Full-text available
In the present talk we will show two different approachs to study the generation of bimetallic nanoparticles. Firstly, we report a dynamic method to generate bimetallic nanoparticles by collision of two pure individual nanoparticles at different kinetic energies and impact parameters. Depending on such conditions and the chemical nature of the meta...

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