物理化学学报 >> 2010, Vol. 26 >> Issue (02): 447-452.doi: 10.3866/PKU.WHXB20100144

量子化学及计算化学 上一篇    下一篇

烷基取代对罗丹明的电子结构与光谱的影响

雷永林, 霍冀川   

  1. 西南科技大学材料科学与工程学院, 四川 绵阳 621010
  • 收稿日期:2009-06-22 修回日期:2009-09-28 发布日期:2010-01-26
  • 通讯作者: 霍冀川 E-mail:huojichuan@swust.edu.cn

Effect of Alkyl Substitution on the Electronic Structure and Spectrum of Rhodamine

LEI Yong-Lin, HUO Ji-Chuan   

  1. College of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan Province, P. R. China
  • Received:2009-06-22 Revised:2009-09-28 Published:2010-01-26
  • Contact: HUO Ji-Chuan E-mail:huojichuan@swust.edu.cn

摘要:

在密度泛函理论(DFT)的B3LYP水平对不同烷基在不同位置取代形成的8种罗丹明化合物进行结构优化, 并在此基础上应用含时密度泛函理论(TD-DFT)和单激发组态相互作用(CIS)方法分析了取代基对罗丹明的电子结构、前线分子轨道及电子光谱的影响. 计算结果表明, 前线分子轨道主要分布在罗丹明分子的氧杂蒽环上, 罗丹明分子中两个N端的H各只有1个H被烷基取代时, 最高占据轨道(HOMO)在主要共轭环分布最多, 且HOMO和最低未占据轨道(LUMO)分布比例相差最小, 两个N端4个H同时被甲基取代时, 能隙最窄, 对气相最大吸收波长红移程度最大,两个N端4个H同时被乙基取代时, 气相荧光最大, 发射波长最长.

关键词: 密度泛函理论, 罗丹明, 烷基取代, 前线分子轨道, 电子光谱

Abstract:

The structures of eight kinds of rhodamine compounds, substituted by different alkyls at different positions, were optimized using the density functional theory (DFT) at the B3LYP level. On the basis of these optimized structures, the influence of the substituting group on the electronic structures and spectral properties as well as frontier molecular orbitals of rhodamine were analyzed using the singlet configuration interaction (CIS) method and time dependent density functional theory (TD-DFT). Results indicate that the frontier molecular orbitals are mainly distributed in the xanthene ring of rhodamine when only one H atom of the two N-ends in the rhodamine molecule is substituted by alkyls. The distribution of the highest occupied molecular orbital (HOMO) is the greatest in the main conjugate ring and the difference in the distribution ratio between the HOMO and the the lowest unoccupied molecular orbital LUMO) is small. When the four H atoms of the two N-ends in the rhodamine molecules are substituted by methyl, the bandgap is found to be the narrowest and the red shift in the gas maximum absorption wavelength is the largest. When the four H atoms of the two N-ends in rhodamine molecules are substituted by ethyl, the gas fluorescence maximum emission wavelength is the longest.

Key words: Density functional theory, Rhodamine, Alkyl substitution, Frontier molecular orbital, Electronic spectrum

MSC2000: 

  • O641