Molecular electronic density fitting using elementary Jacobi rotations under atomic shell approximation
Molecular electronic density fitting using elementary Jacobi rotations under atomic shell approximation
复制标题
DOI：
10.1021/ci0000272
复制
发表时间：
2000-09-01
期刊：
影响因子：
--
通讯作者：
Carbó-Dorca, R
中科院分区：
文献类型：
--
作者：
Amat, L;Carbó-Dorca, R
拟合的电子密度函数构成了量子相似性研究的重要一步。这一事实不仅出现在有关量子相似性度量（QSM）的已发表论文中，而且还与所开发的拟合算法的成功相关。正如之前的工作所证明的那样，可以使用原子壳层近似（ASA）精确拟合电子密度。该方法将电子密度函数表示为球函数的线性组合，并限制展开系数必须是正定的，以保留密度函数作为概率分布的统计意义。最近，基于基本雅可比旋转（EJR）技术的算法被证明是一种有效的电子密度拟合程序。在之前的研究中，采用EJR算法来拟合原子密度函数，随后以亲分子的方式将分子电子密度构建为原子密度的简单总和。继先前建立的计算发展之后，本文将拟合方法应用于分子系统。尽管前分子方法对于量子 QSPR 研究来说足够准确，但某些分子特性（例如静电势）无法使用这种近似水平来描述。本贡献的目的是证明使用前分子 ASA 密度函数作为起点，可以轻松地将 ASA 型函数拟合到 nb 从头分子电子密度。介绍了使用拟合的 6-311G 原子基组对大量分子的前分子和分子 ASA 密度函数进行的比较研究，并讨论了一些应用示例。
Fitted electron density functions constitute an important step in quantum similarity studies. This fact not only is presented in the published papers concerning quantum similarity measures (QSM), but also can be associated with the success of the developed fitting algorithms. As has been demonstrated in previous work, electronic density can be accurately fitted using the atomic shell approximation (ASA). This methodology expresses electron density functions as a linear combination of spherical functions, with the constraint that expansion coefficients must be positive definite, to preserve the statistical meaning of the density function as a probability distribution. Recently, an algorithm based on the elementary Jacobi rotations (EJR) technique was proven as an efficient electron density fitting procedure. In the preceding studies, the EJR algorithm was employed to fit atomic density functions, and subsequently molecular electron density was built in a promolecular way as a simple sum of atomic densities. Following previously established computational developments, in this paper the fitting methodology is applied to molecular systems. Although the promolecular approach is sufficiently accurate for quantum QSPR studies, some molecular properties, such as electrostatic potentials, cannot be described using such a level of approximation. The purpose of the present contribution is to demonstrate that using the promolecular ASA density function as the starting point, it is possible to fit ASA-type functions easily to the nb initio molecular electron density. A comparative study of promolecular and molecular ASA density functions for a large set of molecules using a fitted 6-311G atomic basis set is presented, and some application examples are also discussed.