Miyahara Tomoo, Nakatsuji Hiroshi
Quantum Chemistry Research Institute, Kyoto Technoscience Center 16 , 14 Yoshida Kawara-machi, Sakyou-ku, Kyoto 606-8305, Japan.
J Phys Chem A. 2018 Jan 11;122(1):100-118. doi: 10.1021/acs.jpca.7b09733. Epub 2017 Dec 19.
Accuracy of the time-dependent density functional theory (Td-DFT) was examined for the ultraviolet (UV) and circular dichroism (CD) spectra of deoxyguanosine (dG) and uridine, using 11 different DFT functionals and two different basis sets. The Td-DFT results of the UV and CD spectra were strongly dependent on the functionals used. The basis-set dependence was observed only for the CD spectral calculations. For the UV spectra, the B3LYP and PBE0 functionals gave relatively good results. For the CD spectra, the B3LYP and PBE0 with 6-311G(d,p) basis gave relatively permissible result only for dG. The results of other functionals were difficult to be used for the studies of the UV and CD spectra, though the symmetry adapted cluster-configuration interaction (SAC-CI) method reproduced well the experimental spectra of these molecules. To obtain valuable information from the theoretical calculations of the UV and CD spectra, the theoretical tool must be able to reproduce correctly both of the intensities and peak positions of the UV and CD spectra. Then, we can analyze the reasons of the changes of the intensity and/or the peak position to clarify the chemistry involved. It is difficult to recommend Td-DFT as such tools of science, at least from the examinations using dG and uridine.
使用11种不同的密度泛函理论（DFT）泛函和两种不同的基组，研究了含时密度泛函理论（Td-DFT）对脱氧鸟苷（dG）和尿苷的紫外（UV）光谱和圆二色性（CD）光谱的计算准确性。UV光谱和CD光谱的Td-DFT计算结果强烈依赖于所使用的泛函。仅在CD光谱计算中观察到了基组依赖性。对于UV光谱，B3LYP和PBE0泛函给出了相对较好的结果。对于CD光谱，仅对于dG，采用6-311G(d,p)基组的B3LYP和PBE0给出了相对合理的结果。尽管对称适配团簇组态相互作用（SAC-CI）方法能很好地重现这些分子的实验光谱，但其他泛函的结果难以用于UV和CD光谱的研究。为了从UV和CD光谱的理论计算中获得有价值的信息，理论工具必须能够正确地重现UV和CD光谱的强度和峰位。然后，我们可以分析强度和/或峰位变化的原因，以阐明其中涉及的化学过程。至少从使用dG和尿苷的研究来看，很难推荐将Td-DFT作为这样的科学工具。
