Tags: ab initio

Online Presentations (1-20 of 22)

  1. Lecture 4: The ab-initio Wigner Monte Carlo Method

    18 Nov 2014 | | Contributor(s):: Jean Michel D Sellier

    In this lecture, Dr. Sellier discusses the ab-initio Wigner Monte Carlo method for the simulation of strongly correlated systems.

  2. IMA 2013 UQ: DFT-based Thermal Properties: Three Levels of Error Management

    02 Apr 2014 | | Contributor(s):: Kurt Lejaeghere

    It is often computationally expensive to predict finite-temperature properties of a crystal from density-functional theory (DFT). The temperature-dependent thermal expansion coefficient α, for example, is calculated from the phonon spectrum, and the melting temperature Tm can only be obtained...

  3. Tutorial 1: Atomistic Material Science - ab initio simulations of materials

    03 Nov 2011 | | Contributor(s):: Alejandro Strachan

    This lecture introduces first principles electronic structure calculations of materials properties.It describes the approximations made to the many-body Schrodinger equation in Hartree Fock and Density Functional Theory and numerical approximations used in computer simulations.

  4. OPV: Time Domain Ab Initio Studies of Organic-Inorganic Composites for Solar Cells

    31 Jan 2011 | | Contributor(s):: Oleg Prezhdo

    This presentation was part of the "Organic Photovoltaics: Experiment and Theory" workshop at the 2010 Users' Meeting of the Molecular Foundry and the National Center for Electron Microscopy, both DOE-funded Research Centers at Lawrence Berkeley National Laboratory.

  5. OPV: Large Scale Ab Initio Simulation for Charge Transport in Disordered Organic Systems

    31 Jan 2011 | | Contributor(s):: Lin-Wang Wang

    This presentation was part of the "Organic Photovoltaics: Experiment and Theory" workshop at the 2010 Users' Meeting of the Molecular Foundry and the National Center for Electron Microscopy, both DOE-funded Research Centers at Lawrence Berkeley National Laboratory.

  6. Tutorial 3b: Materials Simulation by First-Principles Density Functional Theory II

    14 Sep 2010 | | Contributor(s):: Umesh V. Waghmare

  7. Ripples and Warping of Graphene: A Theoretical Study

    08 Jun 2010 | | Contributor(s):: Umesh V. Waghmare

    We use first-principles density functional theory based analysis to understand formation of ripples in graphene and related 2-D materials. For an infinite graphene, we show that ripples are linked with a low energy branch of phonons that exhibits quadratic dispersion at long wave-lengths. Many...

  8. MSE 597G Lecture 6: Interatomic potentials III

    12 Nov 2008 | | Contributor(s):: Alejandro Strachan

    Reactive force fields,Parameterization of interatomic potentials

  9. BNC Annual Research Review: An Introduction to PRISM and MEMS Simulation

    04 Jun 2008 | | Contributor(s):: Jayathi Murthy

    This presentation is part of a collection of presentations describing the projects, people, and capabilities enhanced by research performed in the Birck Center, and a look at plans for the upcoming year.

  10. Dynamics of Quantum Fluids: Path integral and Semiclassical Methods

    21 May 2008 | | Contributor(s):: Nancy Makri

    The interplay of many-body nonlinear interactions and quantum mechanical effects such as zero-point motion or identical particle exchange symmetries lead to intriguing phenomena in low-temperature fluids, some of which remain poorly understood. Recent advances in theory and methodology have...

  11. "Ab Initio" Theory of Novel Micro and Nanolasers

    19 May 2008 | | Contributor(s):: A. Douglas Stone

    While the laser is one of the most important inventions of the past century and one of the most interesting and controllable non-linear systems in physics, there is surprisingly little predictive theory of lasing properties. Predicting lasing thresholds and output power far above threshold in...

  12. 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...

  13. Exploring Physical and Chemical control of molecular conductance: A computational study

    31 Jan 2008 | | Contributor(s):: Barry D. Dunietz

  14. Dynamics on the Nanoscale: Time-domain ab initio studies of quantum dots, carbon nanotubes and molecule-semiconductor 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...

  15. Finite Size Scaling and Quantum Criticality

    02 Jan 2008 | | Contributor(s):: Sabre Kais

    In statistical mechanics, the finite size scaling method provides a systematic way to extrapolate information about criticality obtained from a finite system to the thermodynamic limit. For quantum systems, the finite size corresponds not to the spatial dimension but to the number of elements in...

  16. Excellence in Computer Simulation: Computational Materials

    20 Dec 2007 | | Contributor(s):: Eric Schwegler

    This presentation was one of 13 presentations in the one-day forum, "Excellence in Computer Simulation," which brought together a broad set of experts to reflect on the future of computational science and engineering.

  17. Perspectives on Computational Quantum Chemistry

    20 Dec 2007 | | Contributor(s):: Martin P. Head-Gordon

    This presentation was one of 13 presentations in the one-day forum, "Excellence in Computer Simulation," which brought together a broad set of experts to reflect on the future of computational science and engineering.

  18. Computational Mathematics: Role, Impact, Challenges

    20 Dec 2007 | | Contributor(s):: Juan C. Meza

    This presentation was one of 13 presentations in the one-day forum, "Excellence in Computer Simulation," which brought together a broad set of experts to reflect on the future of computational science and engineering.

  19. MCW07 Electronic Level Alignment at Metal-Molecule Contacts with a GW Approach

    05 Sep 2007 | | Contributor(s):: Jeffrey B. Neaton

    Most recent theoretical studies of electron transport in single-molecule junctions rely on a Landauer approach, simplified to treat electron-electron interactions at a mean-field level within density functional theory (DFT). While this framework has proven relatively accurate for certain...

  20. MCW07 Modeling Charging-based 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...