PI-ASTERISK AND SIGMA-ASTERISK EXCITONS IN C-1S ABSORPTION OF GRAPHITE
PI-ASTERISK AND SIGMA-ASTERISK EXCITONS IN C-1S ABSORPTION OF GRAPHITE
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DOI：
10.1103/physrevlett.74.614
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发表时间：
1995-01-23
影响因子：
8.6
通讯作者：
MARTENSSON, N
中科院分区：
文献类型：
--
作者：
BRUHWILER, PA;MAXWELL, AJ;MARTENSSON, N
我们利用核心级自电离光谱研究了石墨C 1 s X射线吸收光谱中的π*和σ*阈值结构。我们确认 σ* 阈值特征是激子。我们发现突出的 π* 特征也是激子性的，尽管它比 π* 阈值高出大约 1 eV。尽管该激发态随着晶体的传播态而简并，但其时间尺度为 fs。
We have studied the π* and σ* threshold structures in the C 1 s x-ray absorption spectrum of graphite using core level autoionization spectroscopy. We confirm that the σ* threshold feature is an exciton. We find that the prominent π* feature is also excitonic, though it lies approximately 1 eV above the π* threshold. This excited state is localized on a time scale of fs, even though it is degenerate with propagating states of the crystal.