Calculation of refractive indices and third-harmonic generation susceptibilities of liquid benzene and water: Comparison of continuum and discrete local-field theories

摘要

The refractive indices (liear response) and the nonlinear susceptibility fo rthird harmonic generation(THG) at #lambda#=1064 nm of liquid water and benzene are predicted, suing ab initio molecular (hyper)polarizatilities and local-field corrections calculated according to the Lorentz model, the generalized reaction-field model of Onsager,a nd a discrete local-field theory applied to liquid structures obtianed by classical molecular simulation methods. The ratio of the calculated THG susceptibilities for the two liquids is compared with experimental results, inorder to avoid ambiguities concerning the factors used to calibrate the THG experimetns. All models are able to reproduce the experiemntal refractive indices of both liquids accurately, but are less successful for the THG susceptibility. The discrete local-field corrections for the THG susceptibility are considerably larger than those of the continuum model in the form of the more accurate extended reaction-field approach.