Babin Volodymyr, Medders Gregory R, Paesani Francesco
Department of Chemistry and Biochemistry, University of California , San Diego, La Jolla, California 92093, United States.
J Chem Theory Comput. 2014 Apr 8;10(4):1599-607. doi: 10.1021/ct500079y. Epub 2014 Mar 21.
A full-dimensional potential energy function (MB-pol) for simulations of water from the dimer to bulk phases is developed entirely from "first principles" by building upon the many-body expansion of the interaction energy. Specifically, the MB-pol potential is constructed by combining a highly accurate dimer potential energy surface [J. Chem. Theory Comput. 2013, 9, 5395] with explicit three-body and many-body polarization terms. The three-body contribution, expressed as a combination of permutationally invariant polynomials and classical polarizability, is derived from a fit to more than 12000 three-body energies calculated at the CCSD(T)/aug-cc-pVTZ level of theory, imposing the correct asymptotic behavior as predicted from "first principles". Here, the accuracy of MB-pol is demonstrated through comparison of the calculated third virial coefficient with the corresponding experimental data as well as through analysis of the relative energy differences of small clusters.
通过基于相互作用能的多体展开，从“第一原理”出发开发了一种用于从二聚体到体相水模拟的全维势能函数（MB-pol）。具体而言，MB-pol 势能是通过将高精度的二聚体势能面[《化学理论与计算杂志》2013 年，9 卷，5395 页]与明确的三体和多体极化项相结合而构建的。三体贡献表示为置换不变多项式和经典极化率的组合，它是通过拟合在 CCSD(T)/aug-cc-pVTZ 理论水平下计算的 12000 多个三体能量得出的，并施加了从“第一原理”预测的正确渐近行为。在此，通过将计算的第三维里系数与相应的实验数据进行比较，以及通过分析小团簇的相对能量差，证明了 MB-pol 的准确性。
