论文标题
层次结构配置互动：结合资历编号和激发学位
Hierarchy Configuration Interaction: Combining Seniority Number and Excitation Degree
论文作者
论文摘要
我们提出了希尔伯特空间，层次结构相互作用（HCI）的新颖分区，其中激发程度（相对于给定的参考决定因素）和资历编号（即，未配对电子的数量）合并为单个层次结构参数。 HCI的关键吸引力是，每个层次结构级别都会说明所有类别的决定因素与系统大小共享相同缩放的决定因素。通过调查多个分子系统的解离，我们发现HCI的整体性能通常超过或至少是基于激发的CI的相似之处。对于较高的HCI和基于激发的CI，与Hartree-Fock轨道获得的结果相比，与轨道优化相关的额外计算负担通常不会补偿边际改进。例外是轨道优化的CI，带有单个激发，这是一个最小相关的模型，以非常适中的计算成本显示了对单键断裂的定性正确描述。
We propose a novel partitioning of the Hilbert space, hierarchy configuration interaction (hCI), where the excitation degree (with respect to a given reference determinant) and the seniority number (i.e., the number of unpaired electrons) are combined in a single hierarchy parameter. The key appealing feature of hCI is that each hierarchy level accounts for all classes of determinants whose number share the same scaling with system size. By surveying the dissociation of multiple molecular systems, we found that the overall performance of hCI usually exceeds or, at least, parallels that of excitation-based CI. For higher orders of hCI and excitation-based CI, the additional computational burden related to orbital optimization usually do not compensate the marginal improvements compared with results obtained with Hartree-Fock orbitals. The exception is orbital-optimized CI with single excitations, a minimally correlated model displaying the qualitatively correct description of single bond breaking, at a very modest computational cost.
