dorsal/arxiv
View SchemaMolecular theories and simulation of ions and polar molecules in water
| Authors | Gerhard Hummer, Lawrence R. Pratt, Angel E. Garcia |
|---|---|
| Categories | |
| ArXiv ID | physics/9806023 |
| URL | https://arxiv.org/abs/physics/9806023 |
| DOI | 10.1021/jp982195r |
| Journal | J. Phys. Chem. A 102, 7885 (1998) |
Abstract
Recent developments in molecular theories and simulation of ions and polar molecules in water are reviewed. The hydration of imidazole and imidazolium solutes is used to exemplify the theoretical issues. The treatment of long-ranged electrostatic interactions in simulations is discussed extensively. It is argued that the Ewald approach is an easy way to get correct hydration free energies in the thermodynamic limit from molecular calculations; and that molecular simulations with Ewald interactions and periodic boundary conditions can also be more efficient than many common alternatives. The Ewald treatment permits a conclusive extrapolation to infinite system size. The picture that emerges from testing of simple models is that the most prominent failings of the simplest theories are associated with solvent proton conformations that lead to non-gaussian fluctuations of electrostatic potentials. Thus, the most favorable cases for the second-order perturbation theories are monoatomic positive ions. For polar and anionic solutes, continuum or gaussian theories are less accurate. The appreciation of the specific deficiencies of those simple models have led to new concepts, multistate gaussian and quasi-chemical theories, that address the cases for which the simpler theories fail. It is argued that, relative to direct dielectric continuum treatments, the quasi-chemical theories provide a better theoretical organization for the computational study of the electronic structure of solution species.
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"abstract": "Recent developments in molecular theories and simulation of ions and polar\nmolecules in water are reviewed. The hydration of imidazole and imidazolium\nsolutes is used to exemplify the theoretical issues. The treatment of\nlong-ranged electrostatic interactions in simulations is discussed extensively.\nIt is argued that the Ewald approach is an easy way to get correct hydration\nfree energies in the thermodynamic limit from molecular calculations; and that\nmolecular simulations with Ewald interactions and periodic boundary conditions\ncan also be more efficient than many common alternatives. The Ewald treatment\npermits a conclusive extrapolation to infinite system size. The picture that\nemerges from testing of simple models is that the most prominent failings of\nthe simplest theories are associated with solvent proton conformations that\nlead to non-gaussian fluctuations of electrostatic potentials. Thus, the most\nfavorable cases for the second-order perturbation theories are monoatomic\npositive ions. For polar and anionic solutes, continuum or gaussian theories\nare less accurate. The appreciation of the specific deficiencies of those\nsimple models have led to new concepts, multistate gaussian and quasi-chemical\ntheories, that address the cases for which the simpler theories fail. It is\nargued that, relative to direct dielectric continuum treatments, the\nquasi-chemical theories provide a better theoretical organization for the\ncomputational study of the electronic structure of solution species.",
"arxiv_id": "physics/9806023",
"authors": [
"Gerhard Hummer",
"Lawrence R. Pratt",
"Angel E. Garcia"
],
"categories": [
"physics.chem-ph",
"physics.bio-ph"
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"doi": "10.1021/jp982195r",
"journal_ref": "J. Phys. Chem. A 102, 7885 (1998)",
"title": "Molecular theories and simulation of ions and polar molecules in water",
"url": "https://arxiv.org/abs/physics/9806023"
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