arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv physics/0303062physics.chem-phphysics.bio-ph
收藏

离子、离子-水团簇和准化学理论的绝对水合自由能

Absolute Hydration Free Energies of Ions, Ion-Water Clusters, and Quasi-chemical Theory

D. Asthagiri, Lawrence R. Pratt, H. S. Ashbaugh

摘要:

离子水簇的实验研究提供了深入了解水合现象的微观方面。一种普遍的观点是,将这些实验研究扩展到更大的簇尺寸将得到单离子绝对水合自由能,这是经典热力学方法无法获得的。这个问题是重新分析的背景下,最近的计算和离子水合的分子理论,特别是考虑水合H $^+$,锂$^+$,钠$^+$,HO $^-$离子和中性离子对的水合。这里计算的中性对的水化自由能与实验结果吻合良好,而计算的绝对水化自由能,和过量化学势,偏离一致,从最近列出的水化自由能的离子-水簇数据的基础上。我们展示了如何单离子绝对水合自由能不分离的潜在的相在最近的分析离子-水簇的数据,即使在限制大集群的大小。我们的结论是,天真的计算离子水团簇应该同意从离子水团簇的实验研究中得到的结果,因为这两个值包括的贡献,有点无关的本地环境的离子,从潜在的阶段。

英文摘要:

Experimental studies on 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 on 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 on 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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑