Numerical Prediction of NaCl Solubility in Water Using the TIP4P/05 Water Model NaCl/Madrid
Abstract
The solid-liquid equilibrium and solubility of NaCl in water were investigated using molecular dynamics simulations with the NaCl/Madrid force field and the TIP4P/05 water model. Particular attention was given to the influence of the intermolecular cut-off radius, rcut, used to identify ions belonging to the crystalline phase. Simulations were initiated from a NaCl crystal immersed in an aqueous NaCl solution, following the configuration proposed by Manzanilla-Granados et al. After equilibration, the system was analysed over an extended simulation trajectory. The radial distribution function, g(r), was used to establish a physically motivated criterion for distinguishing the crystalline and aqueous phases. Specifically, the first minimum following the principal Na-Cl correlation peak was used to characterise the ionic coordination environment and constrain the range of meaningful cut-off radii. The number of ions remaining in the crystalline phase was then evaluated as a function of rcut, allowing the corresponding solubility to be estimated. The resulting curve exhibits a well-defined inflection point, providing a criterion for identifying the transition between predominantly crystalline and dissolved ionic populations. This approach offers a structural basis for determining NaCl solubility directly from the evolution of the solid-liquid system, avoiding the arbitrary selection of the cut-off distance. The results demonstrate that combining radial distribution functions with cut-off-dependent analysis provides a useful framework for characterising solid-liquid behaviour and estimating the solubility of ionic crystals through molecular dynamics simulations.
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BibTeX
@misc{fuentesazcatl2026numerical,
title = {{Numerical Prediction of NaCl Solubility in Water Using the TIP4P/05 Water Model NaCl/Madrid}},
author = {Raúl Fuentes-Azcatl},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.29163},
eprint = {2610.29163},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.29163},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Numerical Prediction of NaCl Solubility in Water Using the TIP4P/05 Water Model NaCl/Madrid
AU - Raúl Fuentes-Azcatl
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.29163
UR - https://arxiv.org/abs/2610.29163
AB - The solid-liquid equilibrium and solubility of NaCl in water were investigated using molecular dynamics simulations with the NaCl/Madrid force field and the TIP4P/05 water model. Particular attention was given to the influence of the intermolecular cut-off radius, rcut, used to identify ions belonging to the crystalline phase. Simulations were initiated from a NaCl crystal immersed in an aqueous NaCl solution, following the configuration proposed by Manzanilla-Granados et al. After equilibration, the system was analysed over an extended simulation trajectory. The radial distribution function, g(r), was used to establish a physically motivated criterion for distinguishing the crystalline and aqueous phases. Specifically, the first minimum following the principal Na-Cl correlation peak was used to characterise the ionic coordination environment and constrain the range of meaningful cut-off radii. The number of ions remaining in the crystalline phase was then evaluated as a function of rcut, allowing the corresponding solubility to be estimated. The resulting curve exhibits a well-defined inflection point, providing a criterion for identifying the transition between predominantly crystalline and dissolved ionic populations. This approach offers a structural basis for determining NaCl solubility directly from the evolution of the solid-liquid system, avoiding the arbitrary selection of the cut-off distance. The results demonstrate that combining radial distribution functions with cut-off-dependent analysis provides a useful framework for characterising solid-liquid behaviour and estimating the solubility of ionic crystals through molecular dynamics simulations.
ER -