Hyperpolarizabilities of para-nitroaniline and bis[4-(dimethylamino)phenyl] squaraine: The effects of functional/basis set based on TDDFT-SOS method

We have carried out a thorough study on the effects of the functional/basis set in calculating hyperpolarizabilities for para-nitroaniline (PNA) and bis[4-(dimethylamino)phenyl] squaraine (H-Sq) compounds by using time-dependent density-functional theory combined with the sum-over-states method. The results show that the hybrid generalized gradient approximations (HGGAs) can give good agreement with both experimental and theoretical ones for PNA, however, generalized gradient approximations (GGAs) is good for H-Sq. The values of hyperpolarizabilities are not sensitive to basis set effect for our studied compounds. The convergent behaviors and efficiency of various functionals are also discussed.