THEORETICAL-STUDY OF THE COLLECTIVE ELECTRONIC EXCITATIONS IN SINGLE-SHELL AND MULTIPLE-SHELL FULLERENES

The collective electronic response due to the a electrons in one-shell (C-60 and C-240) and two-shell (C-300) fullerenes has been studied us ing the time-dependent density-functional theory. The photoabsorption spectra of C-60 and C-240 are simple and differ a little from each oth er. The C-300 spectrum is the more complex and is dominated by collect ive resonances that involve the pi electron cloud of the two-shell ful lerene. The origin of the features in the spectra has been investigate d by following the development of the response as the electron-electro n interactions are switched on.