使用软粘性偶极 - 四极 - 八极水模型理解多极矩对离子水合作用的结构效应。 - Suppr

Te Jerez A, Ichiye Toshiko

Department of Chemistry, Georgetown University, Washington, DC, 20057.

Chem Phys Lett. 2010 Oct 29;499(4-6):219-225. doi: 10.1016/j.cplett.2010.09.043.

The effects of water multipole moments on the aqueous solvation of ions were determined in Monte Carlo simulations using soft-sticky dipole-quadrupole-octupole (SSDQO) water. Water molecules formed linear hydrogen bonds to Cl(-) using the new SSDQO1 parameters, similar to multi-site models. However, the dipole vector was tilted rather than parallel to the oxygen-Na(+) internuclear vector as in most multi-site model, while experiment and ab initio molecular dynamics simulations generally indicate a range of values between tilted and parallel. By varying the multipoles in SSDQO, the octupole was found to determine the orientation around Na(+). Moreover, analysis of the multipoles of more conventional models is predictive of their performance as solvents.

在蒙特卡罗模拟中，使用软粘性偶极 - 四极 - 八极（SSDQO）水模型确定了水多极矩对离子水合作用的影响。水分子利用新的SSDQO1参数与Cl(-)形成线性氢键，类似于多位点模型。然而，偶极矢量是倾斜的，而不像大多数多位点模型那样与氧 - Na(+)核间矢量平行，而实验和从头算分子动力学模拟通常表明其值介于倾斜和平行之间。通过改变SSDQO中的多极矩，发现八极矩决定了围绕Na(+)的取向。此外，对更传统模型的多极矩分析可以预测它们作为溶剂的性能。