Ion Distributions in Solution

化学部理论和计算计划的这项拨款旨在提高我们对溶液结构和动力学的分子水平的理解。这些进展可以帮助人们预测溶液中的化学反应如何受到离子-离子和离子-溶剂作用力的影响。最近，关于溶液中氧化还原反应的一种范例--亚铁和铁离子之间的电子交换，从水到重水的改变的影响被研究。这一结果促使对离子-水水合物的结构和动力学进行进一步的模型研究。另一个方面涉及介质中波动的偏振场的影响。一种新的理论为通常的介电模型提供了热力学和动力学方面的统一观点；它将被扩展到分子模型。溶液中的离子分布提供了离子对化学反应的影响与其他溶液性质之间的联系，包括活度系数、电导、核磁共振弛豫以及X射线和中子的衍射。目前的研究包括发展溶液中的输运理论，以便摩尔浓度范围内的电导率甚至混合电解质中的电导率可以与离子分布和计算它们的模型相关联。

This grant in the Theoretical and Computational Program of the Chemistry Division is aimed at improving our molecular-level understanding of the structure and dynamics of solutions. Such advances can help one predict how chemical reactions in solution are affected by the ion-ion and ion-solvent forces. Recently the electron exchange between ferrous and ferric ions, a paradigm of oxidation-reduction reactions in solution, was investigated with respect to the effect of changing the solvent from water to heavy water. The results invite further model studies of the structure and dynamics of the ion-water hydration complex. Another aspect concerns effects of fluctuating polarization fields in the medium. A new theory gives a unified view of the thermodynamic and dynamic aspects for the usual dielectric models; it invites being extended to molecular models. The ion distributions in solution provide a connection between the effects of ions on chemical reactions and other solution properties including activity coefficients, electrical conductance, NMR relaxation, and diffraction of x-rays and neutrons. Current research includes the development of the theory of transport in solutions so that conductivity in the molar concentration range and even in mixed electrolytes can be related to the ion distributions and the models from which they are calculated.