基于密度泛函理论的C_(24)H_(38)O_4分子外场效应研究  

Investigation of external electric field effect on C_(24)H_(38)O_4 molecule by density functional theory

作　　者：杜建宾[1,2] 张倩 李奇峰[2] 唐延林[3] Du Jian-Bin1,2 Zhang Qian1 Li Qi-Feng2 Tang Yan-Lin3 1(College of Physics and Electrical Information, Langfang Normal University, Langfang 065000, China） 2） （College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China） 3） （Department of Physics, Guizhou University, Guiyang 550025, China)

机构地区：[1]廊坊师范学院物理与电子信息学院,廊坊065000 [2]天津大学精密仪器与光电子工程学院,天津300072 [3]贵州大学理学院物理系,贵阳550025

出　　处：《物理学报》2018年第6期75-82,共8页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2014YQ060773;2017YFC0803600);河北省教育厅青年基金(批准号:QN2015219);廊坊师范学院自然基金(批准号:LSLY201509)资助的课题~~

摘　　要：各种环境毒物危害着人类的健康,塑化剂更是破坏了食品安全.为研究外电场对塑化剂主要成分之一C_(24)H_(38)O_4(邻苯二甲酸二辛酯,dioctyl phthalate,DOP)的影响,采用密度泛函理论B3LYP方法在6-311G(d,p)基组水平上优化了不同静电场0—0.0125 a.u.(0—6.4278×10~9 V/m)作用下DOP分子的基态几何结构,在此基础上利用同样的方法计算了DOP分子的电偶极矩和分子总能量,最后利用含时密度泛函理论在同一基组下研究了不同外电场对DOP分子紫外-可见(UV-vis)吸收光谱产生的影响,并与实验测得的光谱图进行了比较.结果表明:分子几何构型与电场大小呈现强烈的依赖关系,分子偶极矩随着外电场的增强先减小后增加,而分子总能量随着外电场的增强先增加而后急剧减小;DOP分子激发态的振子强度随着外电场的增强而减小,UV-vis吸收峰显著红移.The C24H38O4 （dioctyl phthalate, DOP） is a main component of the plasticizer. In order to study the influence of external electrical field on molecular structure and spectrum of DOP, the method B3LYP of the density functional theory at B3LYP/6-311G（d, p） level is employed to calculate geometrical parameters of the ground state of DOP molecule under different external electric fields （from 0 to 0.0125 a.u.） in this article. On this basis, the ultraviolet-visible absorption spectrum of DOP is calculated by using the time-dependent density functional theory in the same fundamental group and compared with the ultraviolet absorption peak of the molecules, measured by UNICO ultraviolet and visible spectrophotometer. Finally, by using the time-dependent density functional theory in the same fundamental group, we study wavelengths and oscillator strengths of the first twenty-six excited states of DOP molecule in external electric field. The obtained results are as follows. The strongest absorption of ultraviolet-visible absorption spectrum appears in the end absorption band from n to σ＊ transition. The stronger absorption occurs in the E band of benzene electronic transition from π to π＊. The molecular geometry parameters are strongly dependent on the external field intensity. The dipole moment of DOP molecule is proved to first decrease and then increase with the sharp increase of external field, but the total energy first increases and then decreases with the increase of the external field intensity. The ultraviolet absorption peaks of excited states of DOP are proved to have observably red shift, and the oscillator strength sharply decreases with the increasing of the field intensity.

关 键 词：邻苯二甲酸二辛酯 外电场 密度泛函理论 紫外-可见光谱 

分 类 号：O561[理学—原子与分子物理]