Tags: computational chemistry

All Categories (21-40 of 41)

  1. 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...

  2. Computational Nanoscience, Lecture 20: Quantum Monte Carlo, part I

    15 May 2008 | | Contributor(s):: Elif Ertekin, Jeffrey C Grossman

    This lecture provides and introduction to Quantum Monte Carlo methods. We review the concept of electron correlation and introduce Variational Monte Carlo methods as an approach to going beyond the mean field approximation. We describe briefly the Slater-Jastrow expansion of the wavefunction,...

  3. Computational Nanoscience, Lecture 21: Quantum Monte Carlo, part II

    15 May 2008 | | Contributor(s):: Jeffrey C Grossman, Elif Ertekin

    This is our second lecture in a series on Quantum Monte Carlo methods. We describe the Diffusion Monte Carlo approach here, in which the approximation to the solution is not restricted by choice of a functional form for the wavefunction. The DMC approach is explained, and the fixed node...

  4. Computational Nanoscience, Pop-Quiz

    15 May 2008 | | Contributor(s):: Elif Ertekin, Jeffrey C Grossman

    This quiz summarizes the most important concepts which have covered in class so far related to Molecular Dynamics, Classical Monte Carlo Methods, and Quantum Mechanical Methods.University of California, Berkeley

  5. Computational Nanoscience, Pop-Quiz Solutions

    15 May 2008 | | Contributor(s):: Elif Ertekin, Jeffrey C Grossman

    The solutions to the pop-quiz are given in this handout.University of California, Berkeley

  6. UV/Vis Spectra simulator

    04 Mar 2008 | | Contributor(s):: Baudilio Tejerina

    This tool computes molecular electronic spectra.

  7. 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...

  8. CNDO/INDO

    09 Oct 2007 | | Contributor(s):: Baudilio Tejerina, Jeff Reimers

    Semi-empirical Molecular Orbital calculations.

  9. Computational Nanoscience, Lecture 4: Geometry Optimization and Seeing What You're Doing

    13 Feb 2008 | | Contributor(s):: Jeffrey C Grossman, Elif Ertekin

    In this lecture, we discuss various methods for finding the ground state structure of a given system by minimizing its energy. Derivative and non-derivative methods are discussed, as well as the importance of the starting guess and how to find or generate good initial structures. We also briefly...

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

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

  11. 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...

  12. MIT Atomic-Scale Modeling Toolkit

    15 Jan 2008 | | Contributor(s):: daniel richards, Elif Ertekin, Jeffrey C Grossman, David Strubbe, Justin Riley

    Tools for Atomic-Scale Modeling

  13. 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.

  14. 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.

  15. Excellence in Computer Simulation

    19 Dec 2007 | | Contributor(s):: Mark Lundstrom, Jeffrey B. Neaton, Jeffrey C Grossman

    Computational science is frequently labeled as a third branch of science - equal in standing with theory and experiment, and computational engineering is now an essential component of technology development and manufacturing. The successes of computational science and engineering (CSE) over the...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. Molecular Workbench: An Interface to the Molecular World

    25 Jun 2006 | | Contributor(s):: Charles Xie

    The Molecular Workbench software is a free, open-source modeling and authoring program specifically designed for use in science education. Powered by a set of real-time molecular simulation engines that compute and visualize the motion of particles interacting through force fields, in both 2D...