title: The Uhlenbeck-Ford model: Exact virial coefficients and application as a reference system in fluid-phase free-energy calculations.
abstract: The Uhlenbeck-Ford (UF) model was originally proposed for the theoretical study of imperfect gases, given that all its virial coefficients can be evaluated exactly, in principle. Here, in addition to computing the previously unknown coefficients B11through B13, we assess its applicability as a reference system in fluid-phase free-energy calculations using molecular simulation techniques. Our results demonstrate that, although the UF model itself is too soft, appropriately scaled Uhlenbeck-Ford (sUF) models provide robust reference systems that allow accurate fluid-phase free-energy calculations without the need for an intermediate reference model. Indeed, in addition to the accuracy with which their free energies are known and their convenient scaling properties, the fluid is the only thermodynamically stable phase for a wide range of sUF models. This set of favorable properties may potentially put the sUF fluid-phase reference systems on par with the standard role that harmonic and Einstein solids play as reference systems for solid-phase free-energy calculations.
authors.affiliation: Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-859 Campinas, São Paulo, Brazil.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Paula Leite
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Freitas
authors.affiliation: Instituto de Computação, Universidade Estadual de Campinas, UNICAMP, 13083-852 Campinas, São Paulo Brazil.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Azevedo
authors.affiliation: Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-859 Campinas, São Paulo, Brazil.
authors.forename: Maurice
authors.initials: M
authors.lastname: de Koning