The first and second hypersusceptibility of the La@C82 crystal: Effects of disorder

Abstract Using the Hartree–Fock single-excitation configuration interaction (HF-CI) model in conjunction with the local field method, the linear susceptibility tensor, first hypersusceptibility tensor and second hypersusceptibility tensor of the simple cubic (sc) phase of the La@C 82 crystal are calculated. The HF-CI-type electron–phonon model for the La@C 82 crystal is solved with site disorder. The calculations show that the second hypersusceptibility tensor of the La@C 82 crystal is large. The Coulomb interactions and effects of disorder cause increasing hypersusceptibility tensor. Our results show that the optical excitation in the region where the energy is lower than 4 eV has the strongest nonlinear optical absorption bands in the La@C 82 crystal.