Abstract
Electron-energy-loss spectroscopy has been used to measure the electronic excitations in Li from 0.3 to 288 eV. Plasmon losses at 2.85 and 6.3 eV are in good agreement with optical results. In the region between 15 and 40 eV essentially no fine structure associated with backfolded interband transitions is observed contrary to similar measurements in K. These differences are explained by the different bandfolding in and compounds. The carbon absorption edge shows a sharp Fermi-edge discontinuity followed by a shoulder 0.5 eV to higher energy. This absorption feature is similar to but weaker than what is seen in compounds; while the line shape may be a reflection of C final-state relaxation, a quantitative understanding of this phenomenon is still lacking. The Li absorption edge shows two weak peaks at 57.1 and 58.7 eV, which are assigned to transitions to and to a three-dimensional conduction band, followed by two stronger peaks at 63.0 and 65.2 eV. The latter two exhibit relative intensity changes as a function of orientation leading to their identification as atomiclike transitions to crystal-field-split Li levels.
- Received 3 August 1983
DOI:https://doi.org/10.1103/PhysRevB.28.6681
©1983 American Physical Society