dorsal/arxiv
View SchemaFree energy of liquid water on the basis of quasi-chemical theory and ab initio molecular dynamics
| Authors | D. Asthagiri, Lawrence R. Pratt, J. D. Kress |
|---|---|
| Categories | |
| ArXiv ID | physics/0307017 |
| URL | https://arxiv.org/abs/physics/0307017 |
| DOI | 10.1103/PhysRevE.68.041505 |
Abstract
We use ab initio molecular dynamics as a basis for quasi-chemical theory evaluation of the free energy of water near conventional liquid thermodynamic states. The PW91, PBE, and revised PBE (rPBE) functionals are employed. The oxygen radial density distribution, gOO(r), using the rPBE functional is in reasonable agreement with current experiments, whereas the PW91 and PBE functionals predict a more structured gOO(r). The diffusion coefficient with the rPBE functional is in reasonable accord with experiments. Using a maximum entropy procedure, we obtain x_0 from the coordination number distribution x_n for oxygen atoms having n neighbors. Likewise, we obtain p_0 from p_n, the probability of observing cavities of specified radius containing n water molecules. The probability x_0 is a measure of the local chemical interactions and is central to the quasi-chemical theory of solutions. The probability p_0, central to the theory of liquids, is a measure of the free energy required to open cavities of defined sizes in the solvent. Using these values and a reasonable model for electrostatic and dispersion effects, the hydration free energy of water in water at 314K is calculated to be -5.1kcal/mole with the rPBE functional, in encouraging agreement with the experimental value of -6.1kcal/mole.
{
"annotation_id": "9e386271-fa80-4cef-8cf8-df6d080145af",
"date_created": "2026-03-02T18:00:46.091000Z",
"date_modified": "2026-03-02T18:00:46.091000Z",
"file_hash": "c9a6db9c053708a63a1d03437ce1946e27d162d5c0d14b90db05785e0c08b11a",
"private": false,
"record": {
"abstract": "We use ab initio molecular dynamics as a basis for quasi-chemical theory\nevaluation of the free energy of water near conventional liquid thermodynamic\nstates. The PW91, PBE, and revised PBE (rPBE) functionals are employed. The\noxygen radial density distribution, gOO(r), using the rPBE functional is in\nreasonable agreement with current experiments, whereas the PW91 and PBE\nfunctionals predict a more structured gOO(r). The diffusion coefficient with\nthe rPBE functional is in reasonable accord with experiments. Using a maximum\nentropy procedure, we obtain x_0 from the coordination number distribution x_n\nfor oxygen atoms having n neighbors. Likewise, we obtain p_0 from p_n, the\nprobability of observing cavities of specified radius containing n water\nmolecules. The probability x_0 is a measure of the local chemical interactions\nand is central to the quasi-chemical theory of solutions. The probability p_0,\ncentral to the theory of liquids, is a measure of the free energy required to\nopen cavities of defined sizes in the solvent. Using these values and a\nreasonable model for electrostatic and dispersion effects, the hydration free\nenergy of water in water at 314K is calculated to be -5.1kcal/mole with the\nrPBE functional, in encouraging agreement with the experimental value of\n-6.1kcal/mole.",
"arxiv_id": "physics/0307017",
"authors": [
"D. Asthagiri",
"Lawrence R. Pratt",
"J. D. Kress"
],
"categories": [
"physics.chem-ph",
"physics.bio-ph"
],
"doi": "10.1103/PhysRevE.68.041505",
"title": "Free energy of liquid water on the basis of quasi-chemical theory and ab initio molecular dynamics",
"url": "https://arxiv.org/abs/physics/0307017"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "f889f3b7-8c8d-4cb9-aaaa-84fe63e46f3e",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}