Eur. Phys. J. Special Topics 225, 1621-1628 (2016)
https://doi.org/10.1140/epjst/e2016-60094-x

Regular Article

Chemical potential calculations in dense liquids using metadynamics^*

¹ Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
² Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland
³ Institute for Molecular Engineering, The University of Chicago, Chicago, USA

^a e-mail: michele.parrinello@phys.chem.ethz.ch

Received: 29 March 2016
Revised: 10 June 2016
Published online: 18 July 2016

Abstract

The calculation of chemical potential has traditionally been a challenge in atomistic simulations. One of the most used approaches is Widom's insertion method in which the chemical potential is calculated by periodically attempting to insert an extra particle in the system. In dense systems this method fails since the insertion probability is very low. In this paper we show that in a homogeneous fluid the insertion probability can be increased using metadynamics. We test our method on a supercooled high density binary Lennard-Jones fluid. We find that we can obtain efficiently converged results even when Widom's method fails.