Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany.
J Am Chem Soc. 2014 Jul 23;136(29):10246-9. doi: 10.1021/ja505387c. Epub 2014 Jul 14.
Relaxation of photoexcited chromophores is a key factor determining diverse molecular properties, from luminescence to photostability. Radiationless relaxation usually occurs through state intersections caused by distortions in the nuclear geometry of the chromophore. Using excited-state nonadiabatic dynamics simulations based on algebraic diagrammatic construction, it is shown that this is the case of 9H-adenine in water cluster, but not of 7H-adenine in water cluster. 7H-adenine in water cluster relaxes via a state intersection induced by electron transfer from water to the chromophore. This result reveals an unknown reaction pathway, with implications for the assignment of relaxation mechanisms of exciton relaxation in organic electronics. The observation of photorelaxation of 7H-adenine induced by water-chromophore electron transfer is a proof of principle calling for further computational and experimental investigations to determine how common this effect is.
光激发生色团的弛豫是决定从发光到光稳定性等多种分子性质的关键因素。无辐射弛豫通常通过生色团核几何形状的变形引起的态交叉发生。使用基于代数图论构造的激发态非绝热动力学模拟，表明这是在水团簇中的 9H-腺嘌呤的情况，但不是在水团簇中的 7H-腺嘌呤的情况。水团簇中的 7H-腺嘌呤通过从水到生色团的电子转移诱导的态交叉而弛豫。这一结果揭示了一种未知的反应途径，对有机电子中激子弛豫的弛豫机制的分配具有影响。观察到由水-生色团电子转移引起的 7H-腺嘌呤的光弛豫是一个原理性的证明，需要进一步的计算和实验研究来确定这种效应有多普遍。
