Simulation studies of phase behaviour in highly size asymmetrical mixtures

Condensed Matter lunchtime seminar

Simulation studies of phase behaviour in highly size asymmetrical mixtures

  • Event time: 1:00pm
  • Event date: 28th June 2010
  • Speaker: Nigel Wilding (University of Edinburgh)
  • Location: Room 2511,

Event details

Highly size asymmetrical fluid mixtures arise in a variety of physical contexts, most notably in suspensions of colloidal particles to which much smaller particles have been added in the form of polymers or nanoparticles. Conventional schemes for simulating models of such systems are hamstrung by the difficulty of relaxing the large species in the presence of the small one. In this talk I will describe how the rejection-free geometrical cluster algorithm of Liu and Luijten [PRL 92, 035504 (2004)] can be embedded within a restricted Gibbs ensemble in order to facilitate efficient and accurate studies of fluid phase behaviour of highly size asymmetrical mixtures. After providing a description of the algorithm, I shall summarize the bespoke analysis techniques of Ashton et al [JCP 132, 074111 (2010)] that permit accurate estimates of coexisting densities and critical point parameters. The methods are applied to study the liquid-vapor phase diagram of a particular mixture of Lennard-Jones particles having a 10:1 size ratio. The results reveal qualitatively different behaviour to that expected from the standard depletion picture.

This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..

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