Nonlinear optical properties of C-60 with explicit time-dependent electron dynamics

An explicit electron dynamics approach has been used to calculate the nonlinear optical properties of C-60 and its radical anion. An external perturbation, in the form of an oscillating electric field, induces the time-evolution of the molecular wavefunction. The time-averaged instantaneous dipole moment of the systems gives the molecular response to perturbations of varying field intensities and frequency of oscillation. The polarizabilities and the second-order hyperpolarizabilties have been calculated and are in good qualitative agreement with experimentally available data. In line with previous theoretical and experimental studies, the nonlinear effect is enhanced for the radical species.