Neutral and charged excitations in carbon fullerenes from first-principles many-body theories.
Neutral and charged excitations in carbon fullerenes from first-principles many-body theories.
复制标题
第一原理多体理论中碳富勒烯的中性和带电激发。
DOI：
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发表时间：
2008
影响因子：
4.4
通讯作者：
F. Reboredo
中科院分区：
文献类型：
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作者：
M. L. Tiago;P. R. Kent;R. Q. Hood;F. Reboredo
我们通过比较碳富勒烯C（20）、C（24）、C（50）、C（60）、C（70）和C（80）的低能激发与实验，研究了第一性原理多体理论在纳米尺度下的准确性。通过GW-Bethe-Salpeter方程和扩散量子Monte Carlo方法计算性质。我们批判性地比较这些理论，并评估其准确性对现有的光吸收和光电子能谱数据。第一电离势是一贯良好的再现，是相似的所有富勒烯和方法研究。的电子亲和势和第一三重态激发能显示大量的方法和几何形状的依赖性。这些结果建立了多体理论的有效性，作为可行的替代密度泛函理论在描述受限碳纳米结构的电子性质。我们发现富勒烯的能隙和稳定性之间存在相关性。我们还发现，富勒烯的电子亲和势是非常高的和尺寸无关，这解释了他们的倾向，形成化合物与电子供体阳离子。
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.