Empirical bond polarizability model for fullerenes

摘要: The static polarizability properties and the Raman-scattering intensities in molecular ${\mathrm{C}}_{60}$ ${\mathrm{C}}_{70}$ are found to be well reproduced by a bond model with parameters similar those obtained from studies of hydrocarbons. For Raman spectrum off-resonance infrared laser excitation, fit using first-principles vibrational eigenvectors yields ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\parallel}}}^{\ensuremath{'}}$-${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\perp}}}^{\ensuremath{'}}$=2.30 A${\mathrm{\r{}}}^{2}$, 2${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\perp}}}^{\ensuremath{'}}$+${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\parallel}}}^{\ensuremath{'}}$=2.30 ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\parallel}}}$-${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\perp}}}$=1.28 A${\mathrm{\r{}}}^{3}$ for single bonds ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\parallel}}}^{\ensuremath{'}}$-${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\perp}}}^{\ensuremath{'}}$=2.60 2${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\perp}}}^{\ensuremath{'}}$+${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\parallel}}}^{\ensuremath{'}}$=7.55 ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\parallel}}}$-${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\perp}}}$=0.32 double bonds, (${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\parallel}}}$-${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\perp}}}$) arbitrarily set equal its value ethane, namely, 1.28 A${\mathrm{\r{}}}^{3}$. transferability these is discussed detail. \textcopyright{} 1996 American Physical Society.