Europhys. Lett.
Volume 69, Number 3, February 2005
Page(s) 468 - 474
Section Interdisciplinary physics and related areas of science and technology
Published online 24 December 2004
Europhys. Lett., 69 (3), pp. 468-474 (2005)
DOI: 10.1209/epl/i2004-10345-8

Three-body forces at work: Three-body potentials derived from triplet correlations in colloidal suspensions

C. Russ1, M. Brunner2, C. Bechinger2 and H. H. von Grünberg3

1  Universität Konstanz, Fachbereich Physik - D-78457 Konstanz, Germany
2  Universität Stuttgart, 2. Physikalisches Institut - D-70550 Stuttgart, Germany
3  Karl-Franzens Universität Graz, Institut für Chemie - A-8010 Graz, Austria

received 13 September 2004; accepted in final form 12 November 2004
published online 24 December 2004

Two- and three-particle correlation functions are computed from video-microscopy data of two-dimensional suspensions of charged colloids and inverted to derive the pair and three-body interaction potentials between the colloidal particles. Our method allows to resolve the full spatial dependence of the three-body potentials. Examining colloidal systems at different colloid densities, we find density-independent, attractive three-body potentials, with a minimum of a few kT that is most pronounced in the equilateral triangle configuration.

82.70.Dd - Colloids.
82.70.-y - Disperse systems; complex fluids.
05.20.Jj - Statistical mechanics of classical fluids.

© EDP Sciences 2005