论文标题
激发状态的状态特定配置交互
State-Specific Configuration Interaction for Excited States
论文作者
论文摘要
我们介绍和基准标准，用于激发状态计算，特定于状态的配置互动（$δ$ CI），\ arter {\ arter {该{这是多构型自启示字段的特定实现和多连接配置交互的特定实现。决定因素）。单一和双重激发的核算会产生$δ$ CISD模型，可以通过二阶Epstein-nesbet扰动理论（$δ$ CISD+EN2）或后板戴维森校正（$Δ$ CISD+Q）来改进。这些模型是针对294个参考激发能的庞大而多样的。我们发现，$δ$ CI比标准基于基于基础的CI的CI明显更准确，而在$δ$ CISD和EOM-CC2之间，以及$δ$ CISD+EN2和EOM-CCSD之间的近距离性能。对于较大的系统，$δ$ CISD+Q比EOM-CC2和EOM-CCSD提供了更准确的结果。 $δ$ CI路线可以从封闭壳和开放式壳物种中解决具有挑战性的多差问题，单一和双线兴奋的状态，具有总体可比的精度，因此代表了更具成熟方法的有希望的替代方法。但是，以其当前形式，它仅适用于相对较低的激发态。
We introduce and benchmark a systematically improvable route for excited-state calculations, state-specific configuration interaction ($Δ$CI), \alert{which is a particular realization of multiconfigurational self-consistent field and multireference configuration interaction.} Starting with a reference built from optimized configuration state functions, separate CI calculations are performed for each targeted state (hence state-specific orbitals and determinants). Accounting for single and double excitations produces the $Δ$CISD model, which can be improved with second-order Epstein-Nesbet perturbation theory ($Δ$CISD+EN2) or a posteriori Davidson corrections ($Δ$CISD+Q). These models were gauged against a vast and diverse set of 294 reference excitation energies. We have found that $Δ$CI is significantly more accurate than standard ground-state-based CI, whereas close performances were found between $Δ$CISD and EOM-CC2, and between $Δ$CISD+EN2 and EOM-CCSD. For larger systems, $Δ$CISD+Q delivers more accurate results than EOM-CC2 and EOM-CCSD. The $Δ$CI route can handle challenging multireference problems, singly- and doubly-excited states, from closed- and open-shell species, with overall comparable accuracy, and thus represents a promising alternative to more established methodologies. In its current form, however, it is only reliable for relatively low-lying excited states.
