On the Mechanisms of Triplet Excited State Population in 8-Azaadenine
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- 作者：Jo茫o Paulo Gobbo ; Antonio Carlos Borin
- 刊名：The Journal of Physical Chemistry B
- 出版年：2012
- 出版时间：December 6, 2012
- 年：2012
- 卷：116
- 期：48
- 页码：14000-14007
- 全文大小：358K
- 年卷期：v.116,no.48(December 6, 2012)
- ISSN：1520-5207
文摘
The photophysics of 8-azaadenine (8-AA) has been studied with the CASPT2//CASSCF protocol and ANO-L double-味 basis sets. Stationary equilibrium structures, surface crossings, minimum energy paths, and linear interpolations have been used to study possible mechanisms to populate the lowest triplet state, T13(蟺蟺*), capable of sensitizing molecular oxygen. Our results show that two main mechanisms can occur after photoexcitation to the S21(蟺蟺*) state. The first one is through the S2/S1 conical intersection ((1蟺蟺*/1n蟺*)CI), leading to the S1 (1n蟺*) state minimum, (S1 (1n蟺*))min, where a singlet鈥搕riplet crossing, (1n蟺*/3蟺蟺*)STC, is accessible. The second one starts with the (1蟺蟺*/3n蟺*)STC at the (S2(1蟺蟺*))min, from which the system can evolve to the (T2 (3n蟺*))min, with subsequent population of the T1 excited electronic state, due to the (3n蟺*/3蟺蟺*)CI conical intersection.