论文标题
基于密度膨胀的电子相关性的估计值
Estimates of electron correlation based on density expansions
论文作者
论文摘要
根据可以在原子区域分配相关能量的假设，讨论了分子和其他电子系统相关能量的方法。在一种方法中，电子密度使用严格的电子排斥边界来扩大原子贡献，并且在第二种方法中，相关贡献与基本函数对相关。这些方法不考虑局部激发的详细性质，而是定义每个电子因子的相关能量，该因子是特定原子所独有的。相关因子取决于基函数，并取决于双原子和氢化物分子的构型相互作用计算。将相关能量估计与高水平构型相互作用计算的结果进行比较，该测试集的二十七个分子代表了广泛的键合环境（平均误差为2.6％）。基于截短的CI计算的扩展，其中讨论了使用原子相关因子的虚拟空间中D-和氢P型函数以及动态相关贡献的估计值，并应用于几个分子的解离。
Methods for estimating the correlation energy of molecules and other electronic systems are discussed based on the assumption that the correlation energy can be partitioned between atomic regions. In one method, the electron density is expanded in terms of atomic contributions using rigorous electron repulsion bounds, and, in a second method, correlation contributions are associated with basis function pairs. The methods do not consider the detailed nature of localized excitations, but instead define a correlation energy per electron factor that that is unique to a specific atom. The correlation factors are basis function dependent and are determined by from configuration interaction calculations on diatomic and hydride molecules. The correlation energy estimates are compared with the results of high-level configuration interaction calculations for a test set of twenty-seven molecules representing a wide range of bonding environments (average error of 2.6%). An extension based on truncated CI calculations in which d- and hydrogen p-type functions are eliminated from the virtual space combined with estimates of dynamical correlation contributions using atomic correlation factors is discussed and applied to the dissociation of several molecules.
