Model-free measurement of the pair potential in colloidal fluids using optical microscopy

Abstract

We report a straightforward, model-free approach for measuring pair potentials from particle-coordinate data, based on enforcing consistency between the pair distribution function measured separately by the distance-histogram and test-particle insertion routes. We demonstrate the method's accuracy and versatility in simulations of simple fluids, before applying it to an experimental system composed of superparamagnetic colloidal particles. The method will enable experimental investigations into many-body interactions and allow for effective coarse-graining of interactions from simulations.

arXiv comment8 pages, 3 figures including supplemental material

References in corpus (3)

• Beware of density dependent pair potentials
• Visualizing kinetic pathways of homogeneous nucleation in colloidal crystallization
• Elastic properties of 2D colloidal crystals from video microscopy

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