Theoretical study of the electronic spectrum of magnesium-porphyrin
Theoretical study of the electronic spectrum of magnesium-porphyrin
复制标题
镁卟啉电子能谱的理论研究
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
M. Merchán
中科院分区：
文献类型：
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作者：
Mercedes Rubio;B. Roos;L. Serrano;M. Merchán
多构型自洽场（SCF）和二阶微扰方法已用于研究镁卟啉（MgP）的电子能谱。使用了扩展的 ANO 型基组，包括所有重原子上的极化函数。已经计算了 E1u 对称性的四个允许的单重态，此外还计算了一些禁止跃迁和一些三重态。结果得出了对电子能谱的一致解释，其中 Q 波段包含一个跃迁，B 波段包含两个跃迁，N 波段包含一个跃迁。与测量的能带最大值相比，计算出的跃迁能量始终在 0.1 到 0.5 之间太低。差异的根源在于动态相关性（二阶微扰理论）的近似处理、基组的限制以及所有测量都是在取代的镁卟啉上进行的事实。
Multiconfigurational self-consistent field (SCF) and second order perturbation methods have been used to study the electronic spectrum of magnesium-porphyrin (MgP). An extended ANO-type basis set including polarization functions on all heavy atoms has been used. Four allowed singlet states of E1u symmetry have been computed and in addition a number of forbidden transitions and a few triplet states. The results lead to a consistent interpretation of the electronic spectrum, where the Q band contains one transition, the B band two, and the N band one. The computed transition energies are consistently between 0.1 and 0.5 too low compared to the measured band maxima. The source of the discrepancy is the approximate treatment of dynamic correlation (second order perturbation theory), limitations in the basis set and the fact that all measurements have been made on substituted magnesium porphyrins.