CAJ | 학술논문

应用英国Edinburgh FLS920P稳态‐瞬态荧光光谱仪，对互为同分异构体的胭脂红、苋菜红分子的吸收光谱和荧光光谱实验检测，得到二者的光谱特性参数，并进行对比。分别采用密度泛函理论（DFT ）和含时密度泛函理论（TD‐DFT ）对这两种分子的基态和激发态结构进行优化，将所得基态分子构型进行频率计算，结果显示均无虚频存在，进而比较两分子构型在不同能态下的差异。在此基础上，应用TD‐DFT并结合极化连续介质模型（PCM ）在6‐311＋＋G（d ，p）水平上分别计算二者的吸收光谱和荧光光谱，对两种分子的发光机制、荧光光谱特性差异与分子结构的关系进行了分析。结果表明，两种分子的基态结构均为非平面，它们中的两个萘环不共面，存在一定的夹角；苋菜红含有分子内氢键，且氢键所在萘环的平面性要优于胭脂红分子对应的萘环部分；激发态时二者各自的两个萘环均共平面。量子化学计算得到的光谱理论值与实验结果较为吻合，说明优化所得胭脂红与苋菜红的分子构型基本合理。与苋菜红相比，胭脂红右侧萘环结构的平面性稍差，分子从激发态跃迁回到基态经历了更多的振动和转动，损耗了更多的能量，导致用来产生荧光光子的能量减少，因此，胭脂红的荧光发射波长更长。本文首次得到胭脂红、苋菜红分子基态与激发态下的分子结构信息，并找出二者光谱特性差异的原因，结果可为研究同分异构体分子的光谱特性与分子结构的关系提供参考。
응용영국Edinburgh FLS920P은태‐순태형광광보의，대호위동분이구체적연지홍、현채홍분자적흡수광보화형광광보실험검측，득도이자적광보특성삼수，병진행대비。분별채용밀도범함이론（DFT ）화함시밀도범함이론（TD‐DFT ）대저량충분자적기태화격발태결구진행우화，장소득기태분자구형진행빈솔계산，결과현시균무허빈존재，진이비교량분자구형재불동능태하적차이。재차기출상，응용TD‐DFT병결합겁화련속개질모형（PCM ）재6‐311＋＋G（d ，p）수평상분별계산이자적흡수광보화형광광보，대량충분자적발광궤제、형광광보특성차이여분자결구적관계진행료분석。결과표명，량충분자적기태결구균위비평면，타문중적량개내배불공면，존재일정적협각；현채홍함유분자내경건，차경건소재내배적평면성요우우연지홍분자대응적내배부분；격발태시이자각자적량개내배균공평면。양자화학계산득도적광보이론치여실험결과교위문합，설명우화소득연지홍여현채홍적분자구형기본합리。여현채홍상비，연지홍우측내배결구적평면성초차，분자종격발태약천회도기태경력료경다적진동화전동，손모료경다적능량，도치용래산생형광광자적능량감소，인차，연지홍적형광발사파장경장。본문수차득도연지홍、현채홍분자기태여격발태하적분자결구신식，병조출이자광보특성차이적원인，결과가위연구동분이구체분자적광보특성여분자결구적관계제공삼고。
The Edinburgh FLS920P steady‐instantaneous fluorescence spectrometer was applied on the detection of the absorp‐tion and the emission spectra of ponceau 4R and amaranth ,which are isomers to each other .After that ,the spectral parameters of them were compared .Then ,the density functional theory (DFT ) and time‐dependent density functional theory (TD‐DFT ) were used on the optimization of ponceau 4R and amaranth under the ground and excited state ,respectively ,in order to compare the differences in configurations of them under different states .On the base of the results above ,the absorption and emission spectra of the two isomers were calculated with TD‐DFT ,and the polarized continuum model (PCM ) was applied on the base of 6‐311+ +G (d ,p) .The fluorescence mechanism ,the relationships between the properties of fluorescence spectra and the mo‐lecular geometry were all analyzed .The results shows that ,the structures of the two molecules are non‐planar ,these two naph‐thalene rings are not co‐planar ,respectively ,and there’s hydrogen bond in amaranth .When the two isomers were on the ground state ,the planarity of the naphthalene ring which exists the hydrogen bond mentioned above in amaranth is better than the corre‐sponding part of ponceau 4R .The two isomers are nearly co‐planar when they’re on the excited state .The molecular structures of ponceau 4R and amaranth optimized above are basically reasonable ,for the quantum chemistry calculation spectral results are agree with the experiments .The planarity of the naphthalene rings on the right side in ponceau 4R is worse than that in ama‐ranth ,the ponceau 4R molecule experienced more vibration and rotation from the excited to the ground state ,lost more energy , which lead to the reduction of energy for emitting fluorescent photons .So ponceau 4R has longer fluorescence emission wave‐length than amaranth .In this paper ,the molecular structure information of ponceau 4R and amaranth were obtained ,and the differences of the spectral characteristics between them were found out .The results can provide references for the study of the relationship between the spectral properties and the configuration of isomers .