Liquid State Chemical Physics Professor Denis Evans

We study how the structure and dynamics of fluids are determined by intermolecular forces. Armed with this information we are able to predict macroscopic fluid properties such as surface tension, diffusion coefficients, viscosity coefficients, and thermal conductivity.

We develop computer simulation methods to calculate properties of fluids. The majority of such existing algorithms were either formulated or validated by our Group. These algorithms are based on theoretical understanding of the nature of fluids in nonequilibrium steady states, for example, the properties of a lubricant as it flows between engine parts - journal bearings, piston rings etc.

Our research is interdisciplinary, combining the fields of chemistry, physics, chemical engineering and mathematics.

Current research activities

Fluctuation theorem

This remarkable theorem, developed by our Group, gives an analytic expression for the probability that entropy will be consumed rather than produced in small (nano) systems. It predicts that the Second Law of Thermodynamics, which states that entropy always increases, can be violated for small systems over very short time-scales. This theorem has been demonstrated experimentally, in collaboration with the Polymers and Soft Condensed Matter Group, by following the trajectory of a colloidal particle suspended in water, captured in an optical trap. This theorem has important implications for nanotechnology and biology.

Conjugate pairing rule

We have proved a theorem, the conjugate pairing rule, which shows that a transport coefficient like shear viscosity is related in a direct, quantitative way to the stability of molecular trajectories. A transport coefficient can be calculated from the difference in the stability of molecular trajectories for a steady state and its time reversed ‘antisteady state’. This provides a completely new and more efficient way to calculate transport coefficients like shear velocities.

Annual Research Report   (PDF format)

Group members

Academic Staff:
Professor Denis Evans (Leader)   |   Dr Stephen Williams

Visiting Fellows:
Professor Roger Amos   |   Professor Howard Hanley

Visiting Scholar:
Alan Wouterse

Key publications

1. Steven R. Williams and Denis J. Evans, Linear Response Domain in Glassy System, Phys. Rev. Lett., 96 015701 (2006)
2. Butler B.D., Ayton G., Jepps O.G. and Evans D.J., Configurational temperature: Verification of Monte Carlo simulations, J. Chem. Phys., 109, 6519-6522 (1998).
3. Lue L. and Evans D.J., Configurational temperature for systems with constraints, Phys. Rev. E,62, 4764–4768 (2000).
4. Wang, G.M., Sevick, E.M., Mittag, E., Searles, D.J. and Evans, D.J., Experimental demonstration of violations of the Second Law of Thermodynamics for small systems and short time scales, Phys. Rev. Lett., 89(5), 050601/1–4 (2002).
5. Evans, D.J. and Searles, D.J., The Fluctuation Theorem, Adv. in Phys.51, 1529-1585 (2002).

>>more publications

Denis Evans has been a CSIRO Postdoctoral Fellow at Oxford, a Research Fellow at Cornell University and a Fulbright Fellow at the National Bureau of Standards (USA). He is a Fellow of the Australian Academy of Science and has won a number of awards, including the Frederick White Prize of the Australian Academy of Sciences (1990), the Smith Medal of the RACI (2000) and the Boys-Rahman Lectureship of the Royal Society of Chemisry (2000). He is a member of the Editorial Boards of Molecular Simulation, Molecular Physics and Chemical Physics.

private web page: Denis Evans group photos

Professor D J Evans Research School of Chemistry, Building 35 Australian National University Canberra ACT 0200 AUSTRALIA Ph: +61 2 6125 3767 Fx: +61 2 6125 9611 E-mail: evans@rsc.anu.edu.au