标题： 寡聚苊晶体的结构和激发态性质的第一性原理研究 显示英文标题

标题： Structural and excited-state properties of oligoacene crystals from first principles

摘要： 分子晶体是一类典型的范德华（vdW）结合的有机材料，其激发态性质与光电应用相关。 预测分子晶体的结构和激发态性质对电子结构理论提出了挑战，因为密度泛函理论（DFT）的标准近似无法捕捉长程vdW色散相互作用，也无法得到激发态性质。 在本工作中，我们使用包含vdW力的DFT方法（包括非局部相关泛函和成对校正方法）以及多体微扰理论（MBPT），分别研究了从苯到六苯的整个寡聚烯晶体的几何结构和激发态。 我们发现，vdW方法可以将晶格常数预测到实验测量值的1%以内，与之前报道的相同系统的成对近似方法的准确性相当。 我们进一步发现，激发能对几何结构敏感，但如果使用优化的几何结构，MBPT可以获得与实验相差几个十分之一电子伏特的激发态性质。 我们阐明了MBPT计算的整个烯系列中的带电和中性激发能的趋势，并讨论了MBPT中常用近似的角色。 显示英文摘要

摘要： Molecular crystals are a prototypical class of van der Waals (vdW) bound organic materials with excited state properties relevant for optoelectronics applications. Predicting the structure and excited state properties of molecular crystals presents a challenge for electronic structure theory, as standard approximations to density functional theory (DFT) do not capture long range vdW dispersion interactions and do not yield excited state properties. In this work, we use a combination of DFT including vdW forces) using both non local correlation functionals and pair wise correction methods (together with many body perturbation theory (MBPT) to study the geometry and excited states, respectively, of the entire series of oligoacene crystals, from benzene to hexacene. We find that vdW methods can predict lattice constants within 1 percent of the experimental measurements, on par with the previously reported accuracy of pairwise approximations for the same systems. We further find that excitation energies are sensitive to geometry, but if optimized geometries are used MBPT can yield excited state properties within a few tenths of an eV from experiment. We elucidate trends in MBPT computed charged and neutral excitation energies across the acene series and discuss the role of common approximations used in MBPT.