The hyperpolarizabilities for electric dipole second-harmonic generation (SHG) due to the bilinear combination of an electric field and either the electric-field gradient (μeeq) or the associated magnetic field (τeem), and for electric quadrupole SHG quadratic in the electric field (μqee) have been calculated for the C60 molecule at pump photon energies from 0.5 to 2.2 eV using the valence effective Hamiltonian method with a minimal STO-3G basis: magnetic dipole SHG quadratic in the electric field (τmee) is zero by symmetry in C60. The coefficients exhibit resonances at photon energies near 1.9 for μeeq, 1.4 for μqee, and 2.0 eV for τeem. They are combined with empirical local-field factors and a theoretical local field-gradient tensor to calculate the composite susceptibility χ(2) for SHG from crystalline C60 in the same energy range. The susceptibility shows several resonances that arise from those in μeeq, μqee, and τeem. The results are able to reproduce the magnitudes and signs reported experimentally, subject to a sensitive dependence on photon energy near resonances.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry