Hauptseminar Moderne Simulationsmethoden WS 2009/Fortgeschrittene Molekulardynamik I

"{{{number}}}" is not a number.

Date

20010-01-07

Topic

Fortgeschrittene Molekulardynamik I: Wie man die freie Energie berechnet

Speaker

Andreas Irmler

Tutor

Shervin Rafatnia

Vortrag (500 KB)

Ausarbeitung (267 KB)

Literatur

• Daan Frenkel, Berend Smit.
  Understanding Molecular Simulation: From Algorithms to Applications.
  Part of Computational Science, volume 1. Edition 2.
  Academic Press, San Diego, 2002. ISBN: 978-0-12-267351-1.
  [DOI]

Chapter 7

• David A. Kofke Peter, T. Cummings.
  Quantitative comparison and optimization of methods for evaluating the chemical potential by molecular simulation.
  Molecular Physics: An International Journal at the Interface Between Chemistry and Physics 92(6):973–996, 1997.
  [URL]

Kurz zum Inhalt

The aim of this seminar would be to give a short introduction to free energy and to discuss some methods of calculating this energy in a MC or MD simulation.

In thermodynamics, the term free energy refers to the amount of work that can be extracted from a system. It is a subtraction of the entropy of a system multiplied by a reference temperature (giving the "unusable energy") from the total energy, yielding a thermodynamic state function which represents the "useful energy".

Free energy governs thermodynamic processes; all systems minimize their free energy to reach equilibrium. Therefore, calculating the free energy of a system is of great importance. But doing so in a simulation is not always easy. There are different methods to calculate the free energy of a system in MD or MC simulations. One can mention the thermodynamic integration method, the particle insertion method, overlapping distribution method, umbrella sampling and a few others.

Gliederungsvorschlag

1. Einleitung

2. Thermodynamische Integration

3. Widom's Teilcheneinsetzungsmethode

4. Histogramm-Methoden