The recently proposed multireference adiabatic connection (AC) formalism [Pernal, Phys. Rev. Lett. 120, 013001 (2018)] is applied to recover dynamic electron correlation effects lacking in variational two-electron reduced density matrix (v2RDM)-driven complete active space self-consistent field theory (CASSCF). The AC approach is validated by computing potential energy curves for the dissociation of molecular nitrogen and the symmetric double dissociation of H₂O while enforcing two sets of approximate N-representability conditions in the underlying v2RDM-driven CASSCF calculations (either two-particle or two-particle plus partial three-particle conditions). The AC yields smaller absolute errors than second-order N-electron perturbation theory (NEVPT2) at all molecular geometries for both sets of the N-representability conditions considered. The efficacy of the approach for thermochemistry is also assessed for a set of 31 small-molecule reactions. When imposing partial three-particle N-representability conditions, mean and maximum unsigned errors in reaction energies from the AC are superior to those from NEVPT2.

中文翻译：

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降低密度矩阵驱动的完整主动Apace自洽场，已针对绝热连接的动态相关进行了校正。

最近提出的多引用绝热连接（AC）形式主义[Pernal，物理 牧师 120，013001（2018）]用于恢复在变分两电子减密度矩阵（v2RDM）驱动的完整有源空间自洽场理论（CASSCF）中缺乏的动态电子相关效应。通过计算分子氮的解离和H ₂ O的对称双重解离的势能曲线，同时在基础的v2RDM驱动的CASSCF计算中强制执行两组近似的N表示条件（两个粒子或两个粒子），验证了AC方法的有效性。 -粒子加上部分三粒子条件）。对于两组N的所有分子几何结构，AC产生的绝对误差均小于二阶N电子扰动理论（NEVPT2）。-考虑了代表性条件。还针对31种小分子反应对热化学方法的有效性进行了评估。当施加部分三粒子N可表示性条件时，来自AC的反应能量的平均和最大无符号误差要优于来自NEVPT2的平均和最大无符号误差。