
Forces That Govern Life: On the Way to Understanding Intermolecular Interactions
20 Jul 2017   Contributor(s):: Lyudmila V. Slipchenko
This talk will overview our recent work on the Effective Fragment Potential (EFP) method. EFP is a model potential designed for describing noncovalent interactions. The absence of fitted parameters and a natural partitioning of the interaction energy into Coulomb, polarization, dispersion, and...

Atomistic Simulations of Materials Chemistry: From Nanoelectronics to Energetics
07 Apr 2015   Contributor(s):: Alejandro Strachan
Presentation slides with embedded videos are available for download. Please see the Support Docs tab.

Chemistry of Transition Metal Alloy Nanoparticles with Desired Phase Properties
20 Jun 2011   Contributor(s):: Lichang Wang
In this presentation, I will discuss the results of two alloy nanoparticles, PtAu and PtVFe. I will also present the synergetic results of unraveling PtVFe nanoparticles by coupling computational chemistry with experimental work.

Energy and Nanoscience A More Perfect Union
29 Mar 2009   Contributor(s):: Mark Ratner
Huge problems of energy and sustainability confront the science/engineering community, mankind, and our planet. The energy problem comes in many dimensions, including supply, demand, conservation, transportation, and storage. This overview will stress the nature of these problems, and offer a...

Ionic Selectivity in Channels: complex biology created by the balance of simple physics
05 Jun 2008   Contributor(s):: Bob Eisenberg
An important class of biological molecules—proteins called ionic channels—conduct ions (like Na+ , K+ , Ca2+ , and Cl− ) through a narrow tunnel of fixed charge (‘doping’). Ionic channels control the movement of electric charge and current across biological membranes and so play a role in...

Dynamics of Quantum Fluids: Path integral and Semiclassical Methods
21 May 2008   Contributor(s):: Nancy Makri
The interplay of manybody nonlinear interactions and quantum mechanical effects such as zeropoint motion or identical particle exchange symmetries lead to intriguing phenomena in lowtemperature fluids, some of which remain poorly understood. Recent advances in theory and methodology have...

Calculating Resonances Using a Complex Absorbing Potential
13 Mar 2008   Contributor(s):: Robin Santra
The Siegert (or Gamow) wave function associated with a resonance state is exponentially divergent at large distances from the scattering target. A complex absorbing potential (CAP) provides a computationally simple and efficient technique for calculating the complex Siegert energy of a resonance...

Exploring Physical and Chemical control of molecular conductance: A computational study
31 Jan 2008   Contributor(s):: Barry D. Dunietz

Dynamics on the Nanoscale: Timedomain ab initio studies of quantum dots, carbon nanotubes and moleculesemiconductor interfaces
31 Jan 2008   Contributor(s):: Oleg Prezhdo
Device miniaturization requires an understanding of the dynamical response of materials on the nanometer scale. A great deal of experimental and theoretical work has been devoted to characterizing the excitation, charge, spin, and vibrational dynamics in a variety of novel materials, including...

Perspectives on Computational Quantum Chemistry
20 Dec 2007   Contributor(s):: Martin P. HeadGordon
This presentation was one of 13 presentations in the oneday forum, "Excellence in Computer Simulation," which brought together a broad set of experts to reflect on the future of computational science and engineering.

Computational Mathematics: Role, Impact, Challenges
20 Dec 2007   Contributor(s):: Juan C. Meza
This presentation was one of 13 presentations in the oneday forum, "Excellence in Computer Simulation," which brought together a broad set of experts to reflect on the future of computational science and engineering.

MCW07 Electronic Level Alignment at MetalMolecule Contacts with a GW Approach
05 Sep 2007   Contributor(s):: Jeffrey B. Neaton
Most recent theoretical studies of electron transport in singlemolecule junctions rely on a Landauer approach, simplified to treat electronelectron interactions at a meanfield level within density functional theory (DFT). While this framework has proven relatively accurate for certain...

MCW07 Modeling Chargingbased Switching in Molecular Transport Junctions
23 Aug 2007   Contributor(s):: Sina Yeganeh, , Mark Ratner
We will discuss several proposed explanations for the switching and negative differential resistance behavior seen in some molecular junctions. It is shown that a proposed polaron model is successful in predicting both hysteresis and NDR behavior, and the model is elaborated with image charge...

The basics of quantum Monte Carlo
15 Jun 2007   Contributor(s):: Lucas Wagner, Jeffrey C Grossman, Jeffrey B. Neaton
Quantum Monte Carlo is a highly accurate method to approximately solve the Schrodinger equation. I explain quantum Monte Carlo in a way that should be accessible to someone who is somewhat familiar with quantum mechanics. The discussion is mostly conceptual.Lucas Wagner is a postdoctoral...

Finite Size Scaling and Quantum Criticality
09 May 2007   Contributor(s):: Sabre Kais
The study of quantum phase transitions, which are driven by quantum fluctuations as a consequence of Heisenberg's uncertainty principle, continues to be of increasing interest in the fields of condensed matter and atomic and molecular physics. In this field we have established an analogy between...