8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Wed 711:10-14:00P5.21Bulk liquid structure of a model interpolating betweenhard spheres and Gaussian coresMarkus Burgis 1 and Matthias Schmidt 11 Universität Bayreuth, Theoretische Physik II, Physikalisches Institut, Universitätsstra 3095447, Bayreuth, GermanyUsing Monte Carlo computer simulations and density functional theory we consider a repulsivemodel pair potential that is characterized by two length scales, one describing the range and theother describing the softness of the repulsion. Specifically, the Mayer function is taken to bea superposition of two error functions, which allows to interpolate smoothly between the stepfunction characteristic of hard spheres and the Gaussian core model [1]. For pure systems the pairdistribution function displays the expected loss of structure upon increasing softness. We showthat for mixtures of hard sphere colloids and non-adsorbing ideal polymers, the model potential iswell-suited to describe the effective colloid-polymer interactions, refining the Asakura-Oosawa-Vrij model ext[2]. A description within fundamental measure density functional theory [3], basedon the tensorial-diagrammatic series [4], is discussed.[1] F. H. Stillinger, J. Chem. Phys. 65, 3968 (1976); A. J. Archer and R. Evans, Phys.Rev. E 64, 041501 (2001) and references therein.[2] S. Asakura and F. Oosawa, J. Chem. Phys. 22, 1255 (1954); A. Vrij, Pure Appl. Chem. 48,471 (1976).[3] Y. Rosenfeld, Phys. Rev. Lett. 63, 980 (1989); M. Schmidt et al, Phys. Rev. Lett. 85, 1934(2000).[4] G. Leithall and M. Schmidt, Phys. Rev. E 83, 021201 (2011).21