Solvents Level Dipole Moments

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• 作者：Wenkel Liang ; Xiaosong Li ; Larry R. Dalton ; Bruce H. Robinson ; Bruce E. Eichinger
• 刊名：Journal of Physical Chemistry B
• 出版年：2011
• 出版时间：November 3, 2011
• 年：2011
• 卷：115
• 期：43
• 页码：12566-12570
• 全文大小：706K
• 年卷期：v.115,no.43(November 3, 2011)
• ISSN：1520-5207

文摘

The dipole moments of highly polar molecules measured in solution are usually smaller than the molecular dipole moments that are calculated with reaction field methods, whereas vacuum values are routinely calculated in good agreement with available vapor phase data. Whether from Onsager鈥檚 theory (or variations thereof) or from quantum mechanical methods, the calculated molecular dipoles in solution are found to be larger than those measured. The reason, of course, is that experiments measure the net dipole moment of solute together with the polarized (perturbed) solvent 鈥渃loud鈥?surrounding it. Here we show that the reaction field charges that are generated in the quantum mechanical self-consistent reaction field (SCRF) method give a good estimate of the net dipole moment of the solute molecule together with the moment arising from the reaction field charges. This net dipole is a better description of experimental data than the vacuum dipole moment and certainly better than the bare dipole moment of the polarized solute molecule.