Miles D W, Redington P K, Miles D L, Eyring H
Proc Natl Acad Sci U S A. 1981 Dec;78(12):7521-5. doi: 10.1073/pnas.78.12.7521.
The circular dichroism and electronic absorption of three simple model systems for cytidine and uridine have been measured to 190 nm. The molecular spectral properties (excitation wavelengths, oscillator strengths, rotational strengths, and polarization directions) and electronic transitional patterns were investigated by using wave functions of the entire nucleoside with the goal of establishing the reliability of the theoretical method. The computed electronic absorption quantities were shown to be in satisfactory agreement with experimental data. It was found that the computed optical rotatory strengths of the B2u and E1u electronic transitions and lowest observed n-pi transition are in good agreement with experimental values. Electronic transitions were characterized by their electronic transitional patterns derived from population analysis of the transition density matrix. The theoretical rotational strengths associated with the B2u and E1u transitions stabilize after the use of just a few singly excited configurations in the configuration interaction basis and, hypothetically, are more reliable as indicators of conformation in pyrimidine nucleosides related to cytidine.
已对胞苷和尿苷的三种简单模型系统的圆二色性和电子吸收进行了测量，测量范围至190纳米。通过使用整个核苷的波函数，研究了分子光谱性质（激发波长、振子强度、旋光强度和极化方向）以及电子跃迁模式，目的是确定该理论方法的可靠性。计算得到的电子吸收量与实验数据显示出令人满意的一致性。结果发现，计算得到的B2u和E1u电子跃迁以及最低观测到的n-π跃迁的旋光强度与实验值吻合良好。电子跃迁通过其从跃迁密度矩阵的布居分析得出的电子跃迁模式来表征。在组态相互作用基中仅使用少数单激发组态后，与B2u和E1u跃迁相关的理论旋光强度趋于稳定，并且假设地说，作为与胞苷相关的嘧啶核苷构象的指标，它们更可靠。
