Abstract

We revisit the role of attractions in liquids and apply these concepts to colloidal suspensions. Two means are used to investigate the structure; the pair correlation function and a recently developed topological method. The latter identifies structures topologically equivalent to ground state clusters formed by isolated groups of 5 ≤ m ≤ 13 particles, which are specific to the system under consideration. Our topological methodology shows that, in the case of Lennard-Jones, the addition of attractions increases the system’s ability to form larger (m ≥ 8) clusters, although pair-correlation functions are almost identical. Conversely, in the case of short-ranged attractions, pair correlation functions show a significant response to adding attraction, while the liquid structure exhibits a strong decrease in clustering upon adding attractions. Finally, a compressed, weakly interacting system shows a similar pair structure and topology.

J. Taffs, A. Malins, S. R. Williams & C. P. Royall
The Journal of Chemical Physics 133 (24), 244901 (2010)

DOI: 10.1063/1.3516210
PDF: download
ArXiv: http://arxiv.org/abs/1101.1644