MICROSCOPIC STRUCTURE OF THE SURFACE-PLASMON IN FULLERENES

The microscopic structure of the surface plasmon is investigated in th e fullerenes C-60 and C-70, in particular the contribution to its line shape and linewidth arising from the coupling to the normal modes of vibration of the ions, both at zero and at finite temperature. This co upling is found to be negligible in C-60 at all temperatures, but size able for C-70 already at T = 0, evidencing a weak temperature dependen ce, a feature which is due to the lower equilibrium symmetry of C-70. As a result, Landau damping is found to be the dominant relaxation mec hanism contributing to the large width observed experimentally.