Ortmann F, Hannewald K, Bechstedt F
European Theoretical Spectroscopy Facility, Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany.
J Phys Chem B. 2008 Feb 7;112(5):1540-8. doi: 10.1021/jp076455t. Epub 2008 Jan 16.
We report first principles density functional theory studies on the basic ground state characteristics, dynamic properties, and the electronic structure of guanine crystals. The effect of water molecules within the crystal is studied in detail, and we discuss their influence on the structural, vibrational, and electronic properties. The geometries calculated for various crystal structures are compared with gas-phase calculations and available experimental data. Phonon frequencies and eigenvectors are predicted for intermolecular and intramolecular lattice vibrations. Vibrational and electronic density-of-states are presented and analyzed. The electronic band structure near the fundamental gap is calculated from the Kohn-Sham approach. We find that the former molecular HOMO states form a dispersive band in the pi-pi stacking direction upon condensation resulting in a large bandwidth of 0.83 eV. Consequences for the charge transport in layered van der Waals bonded organic molecular crystals are discussed.
我们报告了关于鸟嘌呤晶体的基本基态特性、动态性质和电子结构的第一性原理密度泛函理论研究。详细研究了晶体内水分子的作用，并讨论了它们对结构、振动和电子性质的影响。将各种晶体结构计算得到的几何结构与气相计算结果及现有的实验数据进行了比较。预测了分子间和分子内晶格振动的声子频率和本征向量。给出并分析了振动和电子态密度。从Kohn-Sham方法计算了基本能隙附近的电子能带结构。我们发现，前分子HOMO态在凝聚时沿π-π堆积方向形成一个色散带，导致带宽为0.83 eV。讨论了层状范德华键合有机分子晶体中电荷传输的后果。
