Bottom-up coarse-grained models for external fields and interfaces
| Autor: | Michael R. DeLyser, William G. Noid |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Equation of state
Work (thermodynamics) Materials science 010304 chemical physics Generalization Interface (Java) Structure (category theory) General Physics and Astronomy 010402 general chemistry 01 natural sciences 0104 chemical sciences Connection (mathematics) Physics::Fluid Dynamics Variational principle 0103 physical sciences Statistical physics Physical and Theoretical Chemistry Potential of mean force |
| Zdroj: | The Journal of Chemical Physics. 153:224103 |
| ISSN: | 1089-7690 0021-9606 |
| Popis: | Bottom-up coarse-grained (CG) models accurately describe the structure of homogeneous systems but sometimes provide limited transferability and a poor description of thermodynamic properties. Consequently, inhomogeneous systems present a severe challenge for bottom-up models. In this work, we examine bottom-up CG models for interfaces and inhomogeneous systems. We first analyze the effect of external fields upon the many-body potential of mean force. We also demonstrate that the multiscale CG (MS-CG) variational principle for modeling the external field corresponds to a generalization of the first Yvon-Born-Green equation. This provides an important connection with liquid state theory, as well as physical insight into the structure of interfaces and the resulting MS-CG models. We then develop and assess MS-CG models for a film of liquid methanol that is adsorbed on an attractive wall and in coexistence with its vapor phase. While pair-additive potentials provide unsatisfactory accuracy and transferability, the inclusion of local-density (LD) potentials dramatically improves the accuracy and transferability of the MS-CG model. The MS-CG model with LD potentials quite accurately describes the wall-liquid interface, the bulk liquid density, and the liquid-vapor interface while simultaneously providing a much improved description of the vapor phase. This model also provides an excellent description of the pair structure and pressure-density equation of state for the bulk liquid. Thus, LD potentials hold considerable promise for transferable bottom-up models that accurately describe the structure and thermodynamic properties of both bulk and interfacial systems. |
| Databáze: | OpenAIRE |
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