Ion aggregation in high salt solutions. VII. The effect of cations on the structures of ion aggregates and water hydrogen-bonding network
Ions in high salt solutions have a strong propensity to form polydisperse ion aggregates with broad size and shape distributions. In a series of previous comparative investigations using femtosecond IR pump-probe spectroscopy, molecular dynamics simulation, and graph theoretical analysis, we have sh...
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Veröffentlicht in: | The Journal of chemical physics 2017-10, Vol.147 (15), p.154107-154107 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Ions in high salt solutions have a strong propensity to form polydisperse ion aggregates
with broad size and shape distributions. In a series of previous comparative
investigations using femtosecond IR pump-probe spectroscopy, molecular dynamics
simulation, and graph theoretical analysis, we have shown that there exists a
morphological difference in the structures of ion aggregates formed in various salt
solutions. As salt concentration increases, the ions in high salt solutions form either
cluster-like structures excluding water molecules or network-like structures entwined with
water hydrogen-bonding networks. Interestingly, such morphological characteristics of the
ion aggregates have been found to be in correlation with the solubility limits of salts.
An important question that still remains unexplored is why certain salts with different
cations have notably different solubility limits in water. Here, carrying out a series of
molecular dynamics simulations of aqueous salt solutions and analyzing the distributions
and connectivity patterns of ion aggregates with a spectral graph analysis method, we
establish the relationship between the salt solubility and the ion aggregate morphology
with a special emphasis on the cationic effects on water structures and ion aggregation.
We anticipate that the understanding of large scale ion aggregate structures revealed in
this study will be critical for elucidating the specific ion effects on the solubility and
conformational stability of co-solute molecules such as proteins in water. |
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ISSN: | 0021-9606 1089-7690 |
DOI: | 10.1063/1.4993479 |