Theoretical Studies On The Nonlinear Optical Properties Of Three Types Organic Complexes

Much attention has been paid to the nonlinear optical materials because they have high nonlinear optical coefficient. The nonlinear optical properties of organic complexes are better than those of the inorganic complexes, so people pay more attention to the organic complexes. The first and second hyperpolarizability tensors of diffenent organic complexes have been calculated, the results show that many factors can affect the nonlinear optical properties.Because the d orbital of the translation metal(Au,Ni,Pd,Pt) can come into being d—πconjugated with theπorbital of organic ligand,the transition metals have many states and the ligands easy to modify, it make sense to study the metal organic complex. The relativistic corrections have been taken into account by the effective-core potential. The geometries of the metal organic complex were optimized at the correspond calculated level and the stable configurations were obtained. We use the MP2,HF methods and different basis sets to study the hyperpolarizabilities of translation metal organic complexes, the calculation results were satisfactory. The influlence of calculation methods,basis sets and the metal properties on the hyperpolarizabilities has been discussed.Many non-metal organic complex have been studied on experiment. The tetra- phenylporphyrine compounds have good conjugated configurations and good nonlinear optical properties. The electronic spectra and the third-order optical nonlinearity properties of six tetra- phenylporphyrine compounds were calculated at B3LYP/6-31+G* level. The results showed that the different ligands attached to the porphyrin ring can make the third-order optical nonlinearity properties change.As the special of the octopolar molecules, a theoretical study of static first hyperpolarizabilities of four octopolar molecules without dipole moments are reported. The series of molecules have been calculated at level HF/D95V. The trend of the calculated values is the same as those obtained by experiment. The electric correlation and solvent effects are estimated from smaller model molecules calculation based on assuming that these effects are same for the model and real molecules.The long-chain conjugated compounds have been studiedfor a long time for their good conjugate. The purpose of our work is to use different basis sets to calculate the nonlinear optical properties of different conjugated compounds and compare the results with the results calculated on the MP2/aug-cc-pVTZ and HF/aug-cc-pVTZ levels. We found that the best basis set is 6-31+G*. For the first-order hyperpolarizabilities of PMI, the SCF values obtained here have an opposite sign to that of correlated calculations, so a correlated treatment is necessary for this kind of calculations.