摘要
荧光寿命和荧光量子产率在揭示同分异构现象对有机分子荧光的影响机制方面具有重要作用,有望成为区分水体中结构相似的有机污染物的光谱参数。对同分异构体蒽和菲的三维荧光光谱、荧光寿命和荧光量子产率进行了研究,结果表明:在三维荧光光谱中,蒽强荧光峰的发射波长相对于菲发生了红移,蒽弱荧光峰的激发波长和发射波长相对于菲均发生了红移;在激发波长为254.5 nm、质量浓度为5 mg/L的条件下,蒽和菲的荧光寿命分别约为4.4 ns和14.9 ns;蒽和菲的最大吸收波长分别为355 nm和292 nm,在25℃、质量浓度为1 mg/L的条件下对应的荧光量子产率分别为(29.07±0.61)%和(4.94±0.12)%。密度泛函理论的计算结果表明:在发射态下,蒽和菲的前线分子轨道能级差ΔE分别为0.28456 eV和0.32577 eV,说明蒽的分子硬度比菲小,蒽较不稳定,其π电子更容易从基态被激发到激发态,因而荧光强度和荧光量子产率比菲大;同时蒽上离域的π电子完成π-π*跃迁所需的时间更短,因此荧光寿命更短。
Fluorescence lifetime(FTM)and fluorescence quantum yield(FQY)play an important role in revealing the mechanism of the effect of isomerism on the fluorescence of organic molecules and are expected to be used as spectral parameters to distinguish between organic pollutants with similar structures in water.The three-dimensional fluorescence spectra,FTM and FQY of the isomers anthracene and phenanthrene were studied.The emission wavelength of the strong fluorescence peak of anthracene has a red shift relative to phenanthrene,and the excitation wavelength and emission wavelength of the weak fluorescence peak of anthracene have a red shift relative to phenanthrene in the three-dimensional fluorescence spectra.With an excitation wavelength of 254.5 nm and a mass concentration of 5 mg/L,the FTM of anthracene and phenanthrene were about 4.4 ns and 14.9 ns,respectively.The maximum absorption wavelengths of anthracene and phenanthrene were 355 nm and 292 nm,respectively.The corresponding FQYs at 25℃and 1 mg/L were(29.07±061)%and(4.94±0.12)%,respectively.Density functional theory calculations showed that in the emission state,the orbital energy gaps(ΔE)between the frontier molecular orbitals of anthracene and phenanthrene were 0.28456 eV and 0.32577 eV,respectively,indicating that the molecular hardness of anthracene is smaller than that of phenanthrene and that anthracene is less stable.Theπelectrons of anthracene are more easily excited from the ground state to the excited state,and hence the fluorescence intensity and FQY are larger than those of phenanthrene.At the same time,the delocalizedπelectrons in anthracene require less time to complete theπ-π*transition,so its FTM is shorter.
作者
孙雅静
沈鉴
程澄
刘传旸
宋逸明
熊秋燃
吴静
唐建设
SUN YaJing;SHEN Jian;CHENG Cheng;LIU ChuanYang;SONG YiMing;XIONG QiuRan;WU Jing;TANG JianShe(School of Environmental and Energy Engineering,Anhui Jianzhu University,Hefei 230601;Research Center of Environmental Technology in Water Pollution Source Identification and Precise Supervision,School of Environment,Tsinghua University,Beijing 100084;Research and Development Center of Advanced Environmental Supervision Technology and Instrument,Research Institute for Environmental Innovation(Suzhou),Tsinghua,Suzhou 215163;Anhui Key Laboratory of Water Pollution Control and Wastewater Reuse,Anhui Jianzhu University,Hefei 230601,China)
出处
《北京化工大学学报（自然科学版）》
CAS
CSCD
北大核心
2023年第2期38-45,共8页
Journal of Beijing University of Chemical Technology(Natural Science Edition)
基金
国家自然科学基金面上项目(22076093)
宁夏回族自治区重点研发计划(2021BEG01002)
北京市科技计划(Z221100005222013)。
关键词
蒽
菲
多环芳烃
三维荧光光谱
荧光量子产率
荧光寿命
密度泛函理论
anthracene
phenanthrene
polycyclic aromatic hydrocarbons
three-dimensional fluorescence spectrum
fluorescence quantum yield
fluorescence lifetime
density functional theory
