Baraldi I, Bruni M C, Costi M P, Pecorari P
Dipartimento di Chimica, Università di Modena, Italy.
Photochem Photobiol. 1990 Aug;52(2):361-74. doi: 10.1111/j.1751-1097.1990.tb04192.x.
The changes that the UV absorption spectrum and the photophysics of uracil undergo under hydrogen substitution or deprotonation, were studied theoretically within the CS-INDO/CI scheme. First of all this method was tested on uracil. It was then used for the calculation of the electronic structure of excited states (Sn, Tn) of a large number of uracil derivatives (1-, 3- and 5-methyluracil; 1,3-, 1,5- and 3,5-dimethyluracil; 5-fluoro- and 5-chlorouracil), including some anions (1- and 3-methyluracil anion). The excited states were obtained in the singly-excited configuration interaction approximation (S-CI) and the correlation effects on (pi pi*) states were studied by including the most important doubly- and triply-excited configurations in the CI. The S-CI wavefunctions were used for the calculation of the most important electronic matrix elements for spin-orbit coupling. The photophysics of these compounds is discussed using Jablonski diagrams.
在CS - INDO/CI理论框架下，研究了尿嘧啶在氢取代或去质子化时紫外吸收光谱和光物理性质的变化。首先，该方法在尿嘧啶上进行了测试。然后，它被用于计算大量尿嘧啶衍生物（1 -、3 - 和5 - 甲基尿嘧啶；1,3 -、1,5 - 和3,5 - 二甲基尿嘧啶；5 - 氟尿嘧啶和5 - 氯尿嘧啶）激发态（Sn、Tn）的电子结构，其中包括一些阴离子（1 - 和3 - 甲基尿嘧啶阴离子）。激发态通过单激发组态相互作用近似（S - CI）获得，并且通过在CI中包含最重要的双激发和三激发组态来研究对（ππ*）态的相关效应。S - CI波函数用于计算自旋 - 轨道耦合最重要的电子矩阵元。利用雅布隆斯基图讨论了这些化合物的光物理性质。
