• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Journal of Chemical Physics >Size-consistent wave functions for nondynamical correlation energy: The valence active space optimized orbital coupled-cluster doubles model
【24h】

Size-consistent wave functions for nondynamical correlation energy: The valence active space optimized orbital coupled-cluster doubles model

机译：非动力相关能量的尺寸一致波函数：价态有效空间优化的轨道耦合簇双精度模型

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The nondynamical correlation energy may be defined as the difference between full configuration interaction within the space of all valence orbitals and a single determinant of molecular orbitals (Hartree-Fock theory). In order to describe bond breaking, diradicals, and other electronic structure problems where Hartree-Fock theory fails, a reliable description of nondynamical correlation is essential as a starting point. Unfortunately, the exact calculation of nondynamical correlation energy, as defined above, involves computational complexity that grows exponentially with molecular size and is thus unfeasible beyond systems of just two of three heavy atoms. We introduce a new hierarchy of feasible approximations to the nondynamical correlation energy based on coupled-cluster theory with variationally optimized orbitals. The simplest member of this hierarchy involves connected double excitations within the variationally optimized valence active space and may be denoted as VOO-CCD, or VOD. VOO-CCD is size-consistent, has computational complexity proportional to the sixth power of molecule size, and is expected to accurately approximate the nondynamical correlation energy in such cases as single bond dissociation, diradicals, and anti-ferromagnetic coupling. We report derails of our implementation of VOO-CCD and illustrate that it does indeed accurately recover the nondynamical correlation energy for challenging multireference problems such as the torsion of ethylene and chemical bond breaking. (C) 1998 American Institute of Physics. [S0021-9606(98)30148-8]. [References: 51]
机译：非动力学相关能可以定义为所有价态轨道空间内的完整构型相互作用与分子轨道的单个决定因素之间的差异（Hartree-Fock理论）。为了描述Hartree-Fock理论失败的键断裂，双基和其他电子结构问题，必须以可靠的非动力学相关性描述为起点。不幸的是，如上所述，非动力学相关能的精确计算涉及计算复杂度，其随着分子大小成指数增长，因此在仅三个重原子中的两个原子系统之外是不可行的。我们基于具有可变优化轨道的耦合聚类理论，为非动力相关能量引入了一种新的可行近似方法。该层次结构中最简单的成员涉及在变化优化的价态有效空间内的相连双激发，可以表示为VOO-CCD或VOD。 VOO-CCD是尺寸一致的，具有与分子大小的六次方成正比的计算复杂度，并且在单键解离，双自由基和反铁磁耦合等情况下，有望精确地逼近非动态相关能。我们报告了VOO-CCD实施的出轨情况，并说明了它确实能够准确地恢复非动态相关能量，以解决具有挑战性的多参考问题，例如乙烯的扭转和化学键断裂。 （C）1998美国物理研究所。 [S0021-9606（98）30148-8]。 [参考：51]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号