Dipartimento di Chimica and INSTM, Università Federico II, Complesso Monte S. Angelo, via Cintia, I-80126 Napoli, Italy.
J Phys Chem A. 2009 Dec 31;113(52):15346-54. doi: 10.1021/jp906278t.
A simple vibronic model aimed at investigating the interplay between bright excitonic states and dark charge-transfer (CT) states in stacked adenine (Ade) nucleobases is presented. Two orbitals (the HOMO and the LUMO) for each Ade site have been included in the electronic Hamiltonian, whose parameters have been fitted to reproduce the main features of the absorption spectra of two stacked 9-methyladenine (9Me-A) molecules, computed in aqueous solution at the PCM/TD-PBE0 level. Three modes for each adenine unit have been included in the Hamiltonian, to describe the main structural changes among the different excited state minima of the adenine stacked dimer, as described at the TD-DFT level. The developed vibronic Hamiltonian (four electronic states and six nuclear coordinates) has been adopted to perform quantum dynamical calculations of a photoexcited Ade stacked dimer, utilizing the multiconfigurational time-dependent Hartree method. The obtained results indicate that the transfer between the bright excitonic state and the CT state is fast and effective.
提出了一个简单的振子模型，旨在研究堆叠腺嘌呤（Ade）碱基中明亮激子态和暗电荷转移（CT）态之间的相互作用。电子哈密顿量中包含了每个 Ade 位置的两个轨道（HOMO 和 LUMO），其参数经过拟合，以重现在 PCM/TD-PBE0 水平下在水溶液中计算的两个堆叠的 9-甲基腺嘌呤（9Me-A）分子的吸收光谱的主要特征。哈密顿量中包含了每个腺嘌呤单元的三个模式，以描述在 TD-DFT 水平下描述的腺嘌呤堆叠二聚体不同激发态最小值之间的主要结构变化。所开发的振子哈密顿量（四个电子态和六个核坐标）已被采用，以利用多组态含时哈特ree 方法对光激发的 Ade 堆叠二聚体进行量子动力学计算。得到的结果表明，明亮激子态和 CT 态之间的转移是快速有效的。
