Excitonic effects in linear and nonlinear optical properties of C-60

A model study of the singlet excitons in C-60 With emphasis on the Coulomb interaction between an excited electron and hole and with the aid of the mo lecular symmetry leads to a physical understanding of the interaction effec ts on the absorption spectra and to an identification of the forbidden exci tons in the third-harmonic generation spectra. These conclusions may be tes ted experimentally on the model predictions related to the optical Kerr eff ect. Briefly discussed is the application of the model to other molecules, small clusters, and quantum dots, with the possibility of an excitonic grou nd state. [S0163-1829(99)06904-0].