Canonical transformation theory from extended normal ordering.
Canonical transformation theory from extended normal ordering.
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来自扩展正态排序的规范变换理论。
DOI：
10.1063/1.2761870
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
G. Chan
中科院分区：
文献类型：
--
作者：
Takeshi Yanai;G. Chan
柳井和Chan [J. Chem. Phys. 124，194 - 106（2006）]的正则变换理论提供了多参考问题中动力学相关的严格的尺寸扩展描述。在这里，我们描述了一个新的公式的理论的基础上扩展正常有序程序的Mukherjee和Kutzelnigg [J.化学物理107，432（1997）]。在水、氮和氧化铁势能曲线的研究中，线性正则变换单、双理论在精度上与一些最好的多参考方法，如多参考平均耦合对泛函，而计算时间（在氧化铁分子的情况下）是两到三个数量级更快，可比的完整的活性空间秒-序微扰理论由于采用了一种新的数值算法求解振幅方程，本文的结果在精度和成本上都比我们以前的研究有了很大的提高。
The canonical transformation theory of Yanai and Chan [J. Chem. Phys. 124, 194106 (2006)] provides a rigorously size-extensive description of dynamical correlation in multireference problems. Here we describe a new formulation of the theory based on the extended normal ordering procedure of Mukherjee and Kutzelnigg [J. Chem. Phys. 107, 432 (1997)]. On studies of the water, nitrogen, and iron oxide potential energy curves, the linearized canonical transformation singles and doubles theory is competitive in accuracy with some of the best multireference methods, such as the multireference averaged coupled pair functional, while computational timings (in the case of the iron oxide molecule) are two to three orders of magnitude faster and comparable to those of the complete active space second-order perturbation theory. The results presented here are greatly improved both in accuracy and in cost over our earlier study as the result of a new numerical algorithm for solving the amplitude equations.