II.Dipole-dipole versus current-current correlations,Hyperpolarizabilities for the one-dimensional infinite single-electron periodic systems.

摘要

Based on Takayama-Lin-Liu-Maki model,analytical expressions for the third-harmonic generation,dc Kerr effect,de-induced second-harmonic optical Kerr effect,optical Kerr effect or intensity-dependent index of refraction,and dc-electric-field-induced optical rectification are derived under the static current-current(J-0J_0)correlation for one-dimensional infinite chains.The results of hyperpolarizabilities under J-0J_0 correlation are then compared with those obtained using the dipole-dipole correlation.The comparison shows that the conventional J-0J_0 correlation,albeit quite successful for the linear case,is incorrect for studying the nonlinear optical properties of periodic systems.