ABSTRACT

A systematically TDHF calculation study on the molecular nonlinear properties of coumarins were carried out. The results reveal that these compounds have relatively strong molecular nonlinearity. Concerning substituent positions the 7-substitution was much effective in enhancing the ² values while the position 4 was inert. The 4- and 7-substituted positions in the molecules show obviously active for the macroscopic nonlinearities especially for the different groups. How to design the excellent coumarin second-order NLO materials is also discussed.