Numerical fitting of molecular properties to Hermite Gaussians
Numerical fitting of molecular properties to Hermite Gaussians
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DOI：
10.1021/jp074817r
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发表时间：
2007-11-29
影响因子：
2.9
通讯作者：
Darden, Thomas A.
中科院分区：
文献类型：
--
作者：
Cisneros, G. Andres;Elking, Dennis;Darden, Thomas A.
提出了一种将网格化的分子性质拟合到Hermite Gaussians的辅助基组（ABS）的方法，类似于密度拟合（DF）方法（Dunlap; et al.J.Chem.Phys.1979，71，4993）。在这个过程中，从头计算的属性（密度，静电势，和/或电场）通过线性或非线性最小二乘法拟合辅助基组（ABS）。计算的拟合系数从数值网格被证明是更强大的解析密度拟合由于忽略了核心的贡献。通过计算一组二聚体的分子间库仑相互作用和交换相互作用来测试拟合系数。结果表明，DF中观察到的数值不稳定性是由ABS试图拟合核心贡献造成的。此外，这种新方法使我们能够减少获得准确拟合所需的函数数量。通过计算4096水箱在周期性边界条件下的库仑能，证明了这一点。使用原子中心厄米高斯，这种计算仅比传统的原子中心点电荷慢一个数量级。
A procedure is presented to fit gridded molecular properties to auxiliary basis sets (ABSs) of Hermite Gaussians, analogous to the density fitting (DF) method (Dunlap; et al. J. Chem. Phys. 1979, 71, 4993). In this procedure, the ab initio calculated properties (density, electrostatic potential, and/or electric field) are fitted via a linear- or nonlinear-least-squares procedure to auxiliary basis sets (ABS). The calculated fitting coefficients from the numerical grids are shown to be more robust than analytic density fitting due to the neglect of the core contributions. The fitting coefficients are tested by calculating intermolecular Coulomb and exchange interactions for a set of dimers. It is shown that the numerical instabilities observed in DF are caused by the attempt of the ABS to fit the core contributions. In addition, this new approach allows us to reduce the number of functions required to obtain an accurate fit. This results in decreased computational cost, which is shown by calculating the Coulomb energy of a 4096 water box in periodic boundary conditions. Using atom centered Hermite Gaussians, this calculation is only I order of magnitude slower than conventional atom-centered point charges.