Beware of density dependent pair potentials

By Ard A. Louis. 2002

311 citations recorded by the source corpus.

Density (or state) dependent pair potentials arise naturally from coarse-graining procedures in many areas of condensed matter science. However, correctly using them to calculate physical properties of interest is subtle and cannot be uncoupled from the route by which they were derived. Furthermore, there is usually no unique way to coarse-grain to an effective pair potential. Even for simple systems like liquid argon, the pair potential that correctly reproduces the pair structure will not generate the right virial pressure. Ignoring these issues in naive applications of density dependent pair potentials can lead to an apparent dependence of thermodynamic properties on the ensemble within which they are calculated, as well as other inconsistencies. These concepts are illustrated by several pedagogical examples, including effective pair potentials for systems with many-body interactions, and the mapping of charged (Debye–Huckel) and uncharged (Asakura–Oosawa) two-component systems onto effective one-component ones. The differences between the problems of transferability and representability for effective potentials are also discussed.

Subfields: Geophysics, Physical and Theoretical Chemistry

View Paper: https://www.semanticscholar.org/paper/e368f25ae76303b4b62d13caa28f0c084549efdf

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In Geophysics

1. ST John
2. K. Katsov
3. Michael Schick
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In Physical and Theoretical Chemistry

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2. K. Katsov
3. Michael Schick
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Citations in the corpus

• Challenges in Multiscale Modeling of Polymer Dynamics (2013, unknown): “transferable to another set of conditions (N , T and V or p), as discussed by Luis [230].”
• Many-Body Coarse-Grained Interactions Using Gaussian Approximation Potentials. (2016, background): “∗In fact, even interactions between atoms can never be exactly represented by pair potentials [24].”
• Biological and synthetic membranes: What can be learned from a coarse-grained description? (2006, methodology): “For example, the internal energy is calculated according to [240]:”
• Thermodynamic consistency in dissipative particle dynamics simulations of strongly nonideal liquids and liquid mixtures (2002, background): “Though generally care must be taken with density-dependent interactions [45], the explicit definition of the MDPD local-density in terms of the neighboring particle positions is a “safe” way to introduce density dependence into the interactions [48, 41].”