论文标题
通过非正交配置交互达到完全相关性：二阶扰动方法
Reaching Full Correlation through Nonorthogonal Configuration Interaction: A Second-Order Perturbative Approach
论文作者
论文摘要
非正交的多差异方法可以预测静态相关的绝热能量，同时通过糖尿病参考状态的结合提供化学见解。但是，使用非正交的多次扩展达到定量准确性仍然是一个重大挑战。在这项工作中，我们向非正交配置相互作用介绍了第一个严格的扰动校正，从而可以可靠地计算出其余的动态相关性。我们的二阶“ NOCI-PT2”理论利用了零级广义的hamiltonian，并使用每种参考决定因素的单一和双重激发构建了一阶相互作用空间。因此，这种方法定义了对常规多扰动理论的严格非正交扩展。我们发现NOCI-PT2可以定量预测多方面势能表面，并为绝热避免的横梁提供特异性的地面和激发态。此外，我们引入了一种明确的假想偏移形式主义，需要移动值，该偏移值比常规多驱动理论中使用的偏移值小。
Nonorthogonal multireference methods can predict statically correlated adiabatic energies while providing chemical insight through the combination of diabatic reference states. However, reaching quantitative accuracy using nonorthogonal multireference expansions remains a significant challenge. In this work, we present the first rigorous perturbative correction to nonorthogonal configuration interaction, allowing the remaining dynamic correlation to be reliably computed. Our second-order "NOCI-PT2" theory exploits a zeroth-order generalised Fock Hamiltonian and builds the first-order interacting space using single and double excitations from each reference determinant. This approach therefore defines the rigorous nonorthogonal extension to conventional multireference perturbation theory. We find that NOCI-PT2 can quantitatively predict multireference potential energy surfaces and provides state-specific ground and excited states for adiabatic avoided crossings. Furthermore, we introduce an explicit imaginary-shift formalism requiring shift values that are an order of magnitude smaller than those used in conventional multireference perturbation theory.
