Photoinduced quantum dynamics of ortho- and para-fulvene: Hindered photoisomerization due to mode selective fast radiationless decay via a conical intersection
Photoinduced quantum dynamics of ortho- and para-fulvene: Hindered photoisomerization due to mode selective fast radiationless decay via a conical intersection
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DOI：
10.1063/1.3089546
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发表时间：
2009-03-28
影响因子：
4.4
通讯作者：
Zilberg, S.
中科院分区：
文献类型：
--
作者：
Alfalah, S.;Belz, S.;Zilberg, S.
在本研究中，我们采用量子化学从头计算和量子动力学模拟相结合的方法研究了帕拉和邻位富烯的光诱导非绝热动力学。我们探讨了两种不同的途径之间的竞争，光异构化和无辐射衰变通过一个圆锥交叉（CI）在平面配置。为此，我们将先前的二维模型（其包括分子扭转和反对称拉伸作为耦合模式[Grohmann，Chem.Phys.338，252（2007）]）扩展到三维模型，还考虑了对称拉伸作为附加振动模式。量子动力学模拟表明，在用单个短激光脉冲激发时，模式选择性运动沿着对称拉伸将系统驱动到CI，随后在富烯的光异构化可以发生之前发生无辐射衰减，从而证实了先前的半经典计算[Bearpark，J. Am. 118，5253（1996）]。此外，我们表明，在平面几何光致异构化和无辐射衰变之间的竞争取决于非绝热耦合强度。
In this study, we investigate the photoinduced nonadiabatic dynamics of para- and ortho-fulvene by a combination of quantum chemical ab initio calculations and quantum dynamical simulations. We explore the competition between two different pathways, the photoisomerization and radiationless decay via a conical intersection (CI) at planar configuration. For this purpose, we extend a previous two-dimensional model which included the molecular torsion and the antisymmetric stretch as a coupling mode [Grohmann , Chem. Phys. 338, 252 (2007)] to a three-dimensional model, taking into account also the symmetric stretch as additional vibrational mode. Quantum dynamical simulations show that upon excitation with a single short laser pulse, the mode selective motion along the symmetric stretch drives the system to the CI, followed by radiationless decay before photoisomerization of fulvene can take place, thus confirming previous semiclassical calculations [Bearpark , J. Am. Chem. Soc. 118, 5253 (1996)]. Moreover, we show that the competition between photoisomerization and radiationless decay at a planar geometry depends on the nonadiabatic coupling strength.