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咪唑氧自由基分子NLO性质的密度泛函理论研究 被引量:3
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作者 杜艳青 仇永清 +3 位作者 范洪玲 孙世玲 苏忠民 王荣顺 《化学学报》 SCIE CAS CSCD 北大核心 2008年第18期2017-2022,共6页
采用密度泛函理论(DFT)UB3LYP方法,在6-31g(d)水平上对2,2'-(1,2-乙炔基-4,1-亚苯基)双[4,4',5,5'-四氢]咪唑氧自由基分子及其异构体的自旋耦合性质进行分析,并结合有限场(FF)方法计算它们的非线性光学(NLO)系数,以探讨咪... 采用密度泛函理论(DFT)UB3LYP方法,在6-31g(d)水平上对2,2'-(1,2-乙炔基-4,1-亚苯基)双[4,4',5,5'-四氢]咪唑氧自由基分子及其异构体的自旋耦合性质进行分析,并结合有限场(FF)方法计算它们的非线性光学(NLO)系数,以探讨咪唑氧环在共轭链不同位置时体系的自旋耦合规律和NLO系数.结果表明,所有体系基态自旋符合自旋极化规则,它们的极化率随自旋多重度的增加而减小;一阶超极化率因受分子对称性影响,对称性不同其一阶超极化率的变化也不同;二阶超极化率呈现随着自旋多重度的增加而增加的趋势.从理论上探讨这些自由基分子自旋耦合规律与NLO活性的关系,为有机自由基NLO材料的分子设计与实验研究提供一定的理论依据。 展开更多
关键词 自由基 自旋耦合 nlo系数 UB3LYP方法
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Theoretical Study on Structural Stability and Nonlinear Optical Properties of Non-conjugated Carbon and Nitrogen Diradical Molecules 被引量:2
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作者 刘海波 仇永清 +2 位作者 杨国春 刘春光 孙世玲 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2011年第11期1619-1627,共9页
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 po... 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. 展开更多
关键词 radical position spin multiplicity nlo coefficients
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