Tiago Murilo L, Kent P R C, Hood Randolph Q, Reboredo Fernando A
Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
J Chem Phys. 2008 Aug 28;129(8):084311. doi: 10.1063/1.2973627.
We investigate the accuracy of first-principles many-body theories at the nanoscale by comparing the low-energy excitations of the carbon fullerenes C(20), C(24), C(50), C(60), C(70), and C(80) with experiment. Properties are calculated via the GW-Bethe-Salpeter equation and diffusion quantum Monte Carlo methods. We critically compare these theories and assess their accuracy against available photoabsorption and photoelectron spectroscopy data. The first ionization potentials are consistently well reproduced and are similar for all the fullerenes and methods studied. The electron affinities and first triplet excitation energies show substantial method and geometry dependence. These results establish the validity of many-body theories as viable alternative to density-functional theory in describing electronic properties of confined carbon nanostructures. We find a correlation between energy gap and stability of fullerenes. We also find that the electron affinity of fullerenes is very high and size independent, which explains their tendency to form compounds with electron-donor cations.
我们通过将碳富勒烯C(20)、C(24)、C(50)、C(60)、C(70)和C(80)的低能激发与实验进行比较，研究了纳米尺度下第一性原理多体理论的准确性。通过GW-贝特-萨尔皮特方程和扩散量子蒙特卡罗方法计算性质。我们严格比较了这些理论，并根据现有的光吸收和光电子能谱数据评估了它们的准确性。所有研究的富勒烯和方法的第一电离势都能得到一致的良好再现且相似。电子亲和能和第一三重态激发能表现出显著的方法和几何依赖性。这些结果确立了多体理论在描述受限碳纳米结构电子性质方面作为密度泛函理论可行替代方案的有效性。我们发现了富勒烯的能隙与稳定性之间的相关性。我们还发现富勒烯的电子亲和能非常高且与尺寸无关，这解释了它们与电子给体阳离子形成化合物的倾向。
