Theoretical Study on Structural Stability and Nonlinear Optical Properties of Non-conjugated Carbon and Nitrogen Diradical Molecules  

作　　者：刘海波 仇永清 杨国春 刘春光 孙世玲 

机构地区：[1]Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University

出　　处：《Chinese Journal of Structural Chemistry》2011年第11期1619-1627,共9页结构化学（英文）

基　　金：Supported by the National Natural Science Foundation of China (20873017);the Natural Science Foundation of Jilin Province (20101154)

摘　　要：The geometrical structures and stability of non-conjugated C5H10 and C3H8N2 singlet and triplet diradical molecules have been investigated at the UCCSD/6-311g^＊＊ level. The effects of molecular structure, radical position, amount of Hartree Hork （HF） exchange and spin multiplicity on the nonlinear optical （NLO） coefficients have been also investigated. The reliable UCCSD results show that the triplets of all diradical molecules are more stable compared to their singlet analogues. In addition, the αs and βtot values of C5H10 and C3H8N2 triplet diradical mo-lecules have been investigated by the UBHandHLYP, UB3LYP, UBLYP, UHF and UCCSD methods. The investigation shows that the variations in αs and βtot values are closely connected to the amount of HF exchange. The increasing amount of HF exchange results in monotonic decreases in αs and βtot values, while the αs and βtot values of singlet diradical molecules and the γs of C5H10 and C3H8N2 singlet and triplet diradical molecules have been studied by the UBHandHLYP method. The results illustrate that the NLO coefficients for our studied non-conjugated carbon and nitrogen diradical species can be tuned by molecular structure, radical position and spin multiplicity, which are very significant for designing NLO materials.The geometrical structures and stability of non-conjugated C5H10 and C3H8N2 singlet and triplet diradical molecules have been investigated at the UCCSD/6-311g^＊＊ level. The effects of molecular structure, radical position, amount of Hartree Hork （HF） exchange and spin multiplicity on the nonlinear optical （NLO） coefficients have been also investigated. The reliable UCCSD results show that the triplets of all diradical molecules are more stable compared to their singlet analogues. In addition, the αs and βtot values of C5H10 and C3H8N2 triplet diradical mo-lecules have been investigated by the UBHandHLYP, UB3LYP, UBLYP, UHF and UCCSD methods. The investigation shows that the variations in αs and βtot values are closely connected to the amount of HF exchange. The increasing amount of HF exchange results in monotonic decreases in αs and βtot values, while the αs and βtot values of singlet diradical molecules and the γs of C5H10 and C3H8N2 singlet and triplet diradical molecules have been studied by the UBHandHLYP method. The results illustrate that the NLO coefficients for our studied non-conjugated carbon and nitrogen diradical species can be tuned by molecular structure, radical position and spin multiplicity, which are very significant for designing NLO materials.

关 键 词：radical position spin multiplicity NLO coefficients 

分 类 号：O621.2[理学—有机化学]