Electronic states of fullerenes and alkaline earth fullerides: Photoemission and inverse photoemission studies
Inverse photoemission studies of the empty electronic states of solid C{sub 60} show ten features within 15 eV of the lowest empty state. Pseudopotential calculations identify the character of the empty states. Band calculations for fcc C{sub 60} demonstrate that dispersion of some of the states, due to intermolecular interaction, reproduces experimental results. Intensity variations of experimental features with incident electron energy reflect their {pi}- and {sigma}-character as well as their symmetries. Resonant coupling is observed between the inverse photoemission decay channel involving the third feature and the radiative decay of a plasmon. the distribution of the valence and conduction band electronic states of solid C{sub 70} have been studied with synchrotron radiation photoemission and inverse photoemission. The results show 16 features in the valence band and 10 in the conduction band. The s- and p-character of these states is identified, with those closest to the Fermi level being attributed to p{sub {pi}}-derived levels. Comparison to results for C{sub 60} shows differences due to reduced molecular symmetry and configurational disorder of the solid. Synchrotron radiation photoemission, inverse photoemission, and x-ray photoemission studies show that the mixing of Mg, Sr, Ca and Ba with C{sub 60} probably reflects electron correlation effects. Core level analysis indicates that Mg{sub x}C{sub 60} fulleride formation occurred for 0 {le} x {le} 6 while Sr{sub x}C{sub 60} and Ca{sub x}C{sub 60} fulleride formation occurred for stoichiometries up to x {approximately} 9 with possible phase separation near x = 3. Ba{sub x}C{sub 60} fulleride formation was hindered by kinetic limitations but thin layer growth at 300 K resulted in stoichiometries up to x{approximately}6.
- Research Organization:
- Minnesota Univ., Crookston, MN (United States)
- OSTI ID:
- 114795
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electronic structure of fullerene and alkali-fulleride films
Metallic and semiconducting phases of metal-doped fullerides