Electronic structure of the trimetal nitride fullerene Dy_3N@C_(80)

摘要

We report on a detailed study of the electronic properties of the newly synthesized trimetal nitride fullerene Dy_3N@C_(80) (isomer Ⅰ) using high-energy spectroscopies as probes. From ultraviolet photoemission and C 1s absorption spectroscopies we observe that the occupied and unoccupied electronic structures of the fullerene cage are very similar to those of other trimetal nitride fullerenes and hence both spectra exhibit the narrow structures corresponding to the molecular states of the C_(80) cage with I_h symmetry. X-ray valence-band and Dy 4d photoemission and Dy 4d edge absorption spectroscopies demonstrate that the valency of encaged Dy ions is essentially trivalent Dy(Ⅲ). An effective Dy valency of 2.8 derived from a comparison of the x-ray valence-band photoemission spectrum with atomic multiplet calculations is bigger than for Sc(Ⅲ) in Sc_3N@C_(80) and slightly smaller than for Tm(Ⅲ) in Tm_3N@C_(80). This indicates that the effective metal valency depends on the size of the metal ions as well as the orbital overlap between the metals and the fullerene cage.