Comment on ‘‘Mean force potential for the calcium–chloride ion pair in water’’ [J. Chem. Phys. 99, 4229 (1993)]
- 22 February 1995
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 102 (8) , 3483-3484
- https://doi.org/10.1063/1.468572
Abstract
The interionic potential of mean force (pmf) for the Ca++–Cl− ion pair in water is computed using the molecular dynamics computer simulation technique. The calculated pmf indicates a stable contact pair (CIP) and a solvent-separated pair (SSIP) centered at 2.9 and 5.0 Å with a 2.8 kcal/mol barrier to dissociation. The SSIP well is about 2.0 kcal/mol deeper than the CIP suggesting that water molecules in the first hydration shell are strongly coordinated to the Ca++ ion. Our results do not agree with the pmf reported recently by Guardia, Robinson, Padro [J. Chem. Phys. 99, 4229 (1993)]. Possible reasons for the discrepancy are discussed.Keywords
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