Zahn K, Maret G, Russ C, von Grünberg H H
Fachbereich Physik, Universität Konstanz, PO Box 5560, 78457 Konstanz, Germany.
Phys Rev Lett. 2003 Sep 12;91(11):115502. doi: 10.1103/PhysRevLett.91.115502. Epub 2003 Sep 9.
We use videomicroscopy to follow the phase-space trajectory of a two-dimensional colloidal model liquid and calculate three-point correlation functions from the measured particle configurations. Approaching the fluid-solid transition by increasing the strength of the pair-interaction potential, one observes the gradual formation of a crystal-like local order due to triplet correlations, while being still deep inside the fluid phase. Furthermore, we show that in a strongly interacting system the Born-Green equation can be satisfied only with the full triplet correlation function but not with three-body distribution functions obtained from superposing pair correlations (Kirkwood superposition approximation).
