Year: 2003
Type: article
Abstract: Experimental studies of ion–water clusters have provided insights into the microscopic aspects of hydration phenomena. One common view is that extending those experimental studies to larger cluster sizes would give the single-ion absolute hydration free energies not obtainable by classical thermodynamic methods. This issue is reanalyzed in the context of recent computations and molecular theories of ion hydration, particularly considering the hydration of H+, Li+, Na+, and HO− ions, and thence the hydration of neutral ion pairs. The hydration free energies of neutral pairs computed here are in good agreement with experimental results, whereas the calculated absolute hydration free energies and the excess chemical potentials deviate consistently from some recently tabulated hydration free energies based on ion–water cluster data. We show how the single-ion absolute hydration free energies are not separated from the potential of the phase in recent analyses of ion–water cluster data, even in the limit of large cluster sizes. We conclude that naive calculations of ion–water clusters ought to agree with results obtained from experimental studies of ion–water clusters because both values include the contribution, somewhat extraneous to the local environment of the ion, from the potential of the phase.
Source: The Journal of Chemical Physics
DOI: 10.1063/1.1587122
Authors: D. Asthagiri, Lawrence R. Pratt, H. S. Ashbaugh
Institution: Los Alamos National Laboratory
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Award: G797745481
OpenAlex ID: W1964471150