Coordination of an axial ligand to metal center to enhance the second-order nonlinear optical（NLO） re- sponse of a two-dimensional bis（salicylaldiminato） zinc（II） Schiff-base complex is an unprecedented model. T...Coordination of an axial ligand to metal center to enhance the second-order nonlinear optical（NLO） re- sponse of a two-dimensional bis（salicylaldiminato） zinc（II） Schiff-base complex is an unprecedented model. The second-order NLO responses of a series of axially substituted bis（salicylaldiminato） zinc（II） Schiff-base complexes were explored according to the finite field（FF） method at CAM-B3LYP/6-31＋G（d） level（LANL2DZ basis set for metal atoms）. The results show that the second-order NLO properties can be effectively tuned by exchanging the do- nor and accepter of the axial ligand and extending the length of the conjugated bridge along the axial direction. A system involving the electron acceptor along the appropriate direction has a large three-dimensional second-order NLO response. Meanwhile, time dependent density functional theory（TD-DFT） method was employed to calculate the physical parameters of excited states. The results show that the Y- and Z-polarized transitions of the zinc（II） Schiff-base complex are the first and second excited states, respectively, and have a low-lying excited energy. Al- though the X-polarized transition has a high excited energy, the large oscillator strength indicates that it will signifi- cantly contribute to the second-order NLO response.展开更多
基金Supported by the National Natural Science Foundation of China（No.21373043）, the Chinese Postdoctoral Science Founda- tion（No.2013M540261）, the Scientific Research Fund for Doctor of Northeast Dianli University, China（No.BSJXM-201110） and the Innovation Fund for Graduate Student of Northeast Dianli University, China.
文摘Coordination of an axial ligand to metal center to enhance the second-order nonlinear optical（NLO） re- sponse of a two-dimensional bis（salicylaldiminato） zinc（II） Schiff-base complex is an unprecedented model. The second-order NLO responses of a series of axially substituted bis（salicylaldiminato） zinc（II） Schiff-base complexes were explored according to the finite field（FF） method at CAM-B3LYP/6-31＋G（d） level（LANL2DZ basis set for metal atoms）. The results show that the second-order NLO properties can be effectively tuned by exchanging the do- nor and accepter of the axial ligand and extending the length of the conjugated bridge along the axial direction. A system involving the electron acceptor along the appropriate direction has a large three-dimensional second-order NLO response. Meanwhile, time dependent density functional theory（TD-DFT） method was employed to calculate the physical parameters of excited states. The results show that the Y- and Z-polarized transitions of the zinc（II） Schiff-base complex are the first and second excited states, respectively, and have a low-lying excited energy. Al- though the X-polarized transition has a high excited energy, the large oscillator strength indicates that it will signifi- cantly contribute to the second-order NLO response.
