Temperature dependence in interatomic potentials and an improved potential for Ti

G. J. Ackland*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The process of deriving an interatomic potentials represents an attempt to integrate out the electronic degrees of freedom from the full quantum description of a condensed matter system. In practice it is the derivatives of the interatomic potentials which are used in molecular dynamics, as a model for the forces on a system. These forces should be the derivative of the free energy of the electronic system, which includes contributions from the entropy of the electronic states. This free energy is weakly temperature dependent, and although this can be safely neglected in many cases there are some systems where the electronic entropy plays a significant role. Here a method is proposed to incorporate electronic entropy in the Sommerfeld approximation into empirical potentials. The method is applied as a correction to an existing potential for titanium. Thermal properties of the new model are calculated, and a simple method for fixing the melting point and solid-solid phase transition temperature for existing models fitted to zero temperature data is presented.

Original languageEnglish
Title of host publicationIUPAP C20 CONFERENCE ON COMPUTATIONAL PHYSICS (CCP 2011)
EditorsGM Stocks, MC Troparevsky
Place of PublicationBRISTOL
PublisherIOP Publishing
Number of pages9
ISBN (Print)*****************
DOIs
Publication statusPublished - 2012
Event23rd IUPAP C20 Conference on Computational Physics (CCP) - Gatlinburg, Tunisia
Duration: 30 Oct 20113 Nov 2011

Publication series

NameJournal of Physics Conference Series
PublisherIOP PUBLISHING LTD
Volume402
ISSN (Print)1742-6588

Conference

Conference23rd IUPAP C20 Conference on Computational Physics (CCP)
Country/TerritoryTunisia
Period30/10/113/11/11

Keywords / Materials (for Non-textual outputs)

  • TRANSITION-METALS
  • CONSISTENT
  • THERMODYNAMICS
  • IMPURITIES
  • ZIRCONIUM
  • SURFACES
  • DEFECTS
  • ALLOYS
  • MODEL
  • FE

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