Three-state conical intersections in nucleic acid bases
Three-state conical intersections in nucleic acid bases
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DOI：
10.1021/jp0513622
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发表时间：
2005-08-25
影响因子：
2.9
通讯作者：
Matsika, S
中科院分区：
文献类型：
--
作者：
Matsika, S
用多参考组态相互作用方法研究了三态锥形交点参与核碱基的光物理和无辐射衰变过程。已经确定了嘧啶碱基尿嘧啶和嘌呤碱腺嘌呤的三态锥形交叉点。在URAIL中，S-0态、S-1态和S-2态之间的三态简并位于基态最低能量上方6.2 eV处。这一能量比S的垂直激发能量高0.4 eV，比以前发现的两态锥形交叉点至少高1.3 eV。在腺嘌呤中，S-1态、S-2态和S-3态之间的两个不同的三态简并位于垂直激发能附近。这些三态锥形交叉点的能量学表明，它们可以在腺嘌呤中存在的无辐射衰变途径中发挥作用。三态锥形交点的两个不同接缝的存在表明，这些特征是常见的，并且使腺嘌呤和可能许多其他芳香族分子的势能面复杂化。
The involvement of three-state conical intersections in the photophysics and radiationless decay processes of the nucleobases has been investigated using multireference configuration interaction methods. Three-state conical intersections have been located for the pyrimidine base, uracil, and the purine base, adenine. In uracil, a three-state degeneracy between the S-0, S-1, and S-2 states has been located at 6.2 eV above the ground-state minimum energy. This energy is 0.4 eV higher than vertical excitation to S and at least 1.3 eV higher than the two-state conical intersections found previously. In adenine, two different three-state degeneracies between the S-1, S-2, and S-3 states have been located at energies close to the vertical excitation energies. The energetics of these three-state conical intersections suggest they can play a role in a radiationless decay pathway present in adenine. The existence of two different seams of three-state conical intersections indicates that these features are common and complicate the potential energy surfaces of adenine and possibly many other aromatic molecules.