Electron correlation effects on the excitation energies of the lowest triplet states of glyoxal
Electron correlation effects on the excitation energies of the lowest triplet states of glyoxal
复制标题
电子相关效应对乙二醛最低三重态激发能的影响
DOI：
10.1063/1.435214
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发表时间：
1977
影响因子：
4.4
通讯作者：
H. Schaefer
中科院分区：
文献类型：
--
作者：
C. E. Dykstra;R. Lucchese;H. Schaefer
为了了解乙二醛激发态的排序，我们使用从头算相关波函数研究了 1Ag 基态和低位三重态 3Au、3Bu 和 3Bg。在构型相互作用计算中使用双 zeta 基组，并为每个电子态选择约 6000 个 Slater 行列式。预测的 CI 绝热激发能 Te 为 21 800 cm−1 (3Au)、25 100 cm−1 (3Bu) 和 29 300 cm−1 (3Bg)。还评估了 d 函数和更高（高于双倍）激发（未连接的簇）的影响。对于 3Bu 态，d 函数和更高的激发都将预测的 Te 值提高了 5 000 cm−1 之多。对于 3Bg 态，d 函数提高了预测的激发能量，但更高的激发具有相反的效果。结论是，3Bu态的激发能因相关效应而显着增加，而3Au和3Bg态的Te因相关效应而显着降低。
In an attempt to understand the ordering of excited states of glyoxal the 1Ag ground state and low‐lying triplet states 3Au, 3Bu, and 3Bg have been studied with ab initio correlated wavefunctions. A double zeta basis set was used in the configuration interaction calculations, and ∼6000 Slater determinants were selected for each electronic state. The predicted CI adiabatic excitation energies Te are 21 800 cm−1 (3Au), 25 100 cm−1 (3Bu), and 29 300 cm−1 (3Bg). The effects of d functions and higher (than double) excitations (unlinked clusters) have also been evaluated. For the 3Bu state, both d functions and higher excitations raise the predicted Te value by perhaps as much as 5 000 cm−1. For the 3Bg state, d functions raise the predicted excitation energy but higher excitations have the opposite effect. It is concluded that the excitation energy of the 3Bu state is dramatically increased by correlation effects, while Te for the 3Au and 3Bg states is markedly decreased by correlation.