(Hyper)polarizability density analysis for open-shell molecular systems based on natural orbitals and occupation numbers
(Hyper)polarizability density analysis for open-shell molecular systems based on natural orbitals and occupation numbers
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DOI：
10.1007/s00214-010-0871-y
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发表时间：
2011-12-01
影响因子：
1.7
通讯作者：
Kamada, Kenji
中科院分区：
文献类型：
--
作者：
Nakano, Masayoshi;Fukui, Hitoshi;Kamada, Kenji
我们发展了一种分析开壳层分子体系（超）极化率的方法。该方法采用基于自然轨道和占据数的（超）极化率密度，这使我们能够分析具有各种开壳层（双自由基）特征的奇电子的贡献。在破缺对称中，即，自旋非限制的、单决定簇的分子轨道和密度泛函理论方法，我们也可以通过自旋投影来消除自旋污染对这些量的影响。为此，我们提出了一种近似的自旋投影方法，并将其应用于多自由基体系（超）极化率的分析。作为例子，典型的开壳层单线态系统，1，3-偶极子和矩形石墨烯纳米片，进行了检查。
We have developed a method for analyzing the (hyper)polarizabilities of open-shell molecular systems. This method employs the (hyper)polarizability densities based on the natural orbitals and occupation numbers, which enables us to analyze the contributions of odd electrons having various open-shell (diradical) characters. Within broken-symmetry, i.e., spin-unrestricted, single-determinant molecular orbital and density functional theory approaches, we can also remove the spin contamination effects on these quantities through spin projection. To do that, an approximate spin projected method has been elaborated and applied to the analysis of the (hyper)polarizability of multi-radical systems. As examples, typical open-shell singlet systems, 1,3-dipoles and rectangular graphene nanoflakes, are examined.