摘要
研究尼古丁分子的能级结构与光谱特征,对更好地了解尼古丁分子的毒性和药性有理论指导作用.基于密度泛函理论(DFT),本文利用Gaussian 09软件在B3LYP/6-311G(d,p)基组水平上对尼古丁分子进行结构优化,再采用含时密度泛函理论(TD-DFT)在乙醇溶剂中计算尼古丁分子的15个激发态.使用Multiwfn波谱分析软件对分子前线轨道进行计算,并绘制出分子的红外谱图和紫外谱图.通过前线轨道分析可知,尼古丁分子的亲核位点是吡啶环上的C3和N6、亲电位点是吡咯环上的N22.吡啶环上的C-H、N-H键面内伸缩振动峰主要集中在3049~3079 cm-1,吡咯环上的甲基、亚甲基的伸缩振动峰主要集中在2796~3005 cm-1,其中在2816 cm-1处甲基上C-H键振动峰最为明显,占比43.3%;吡咯环与吡啶环的摆动峰主要集中在1027~1455 cm-1,吡啶环的面内振动峰主要集中在1008~1027 cm-1,在800 cm-1以下吸收峰都为吡啶环的面外摆动峰.紫外光谱的最大吸收峰位于173.46571 nm处,主要是由基态S0跃迁到激发态S5、S6、S10、S11、S12、S13、S14形成的,其中基态S0跃迁到激发态S11的贡献最大,其余激发态跃迁振子强度小于0.03,为禁阻跃迁.
The study of the energy level structure and spectral characteristics of nicotine molecules has theoretical guidance for better understanding the toxicity and drug properties of nicotine molecules.Based on the density functional theory(DFT),the structure of nicotine molecules was optimized by the Gaussian 09 software at the level of basis set of B3LYP/6-311G(d,p)in this paper.Then the 15 excited states of the nicotine molecule in the ethanol solvent were calculated by time-dependent density functional theory(TD-DFT).The molecular frontier orbit was calculated by using Multiwfn spectral analysis software and the infrared spectrum and ultraviolet spectrum of the nicotine molecules were plotted.According to the analysis of frontier orbit,the nucleophilic sites of nicotine molecules are C3 and N6 on the pyridine ring and its electrophilic sites is N22 on the pyrrole ring.The in-plane stretching vibration peaks of C-H and N-H bond on the pyridine ring are mainly concentrated at 3049~3079 cm-1,and the in-plane stretching vibration peaks of methyl and methylene on the pyrrole ring are mainly concentrated at 2796~3005 cm-1.Among them,the C-H bond vibration peak at on the methyl group 2816 cm-1 is the most obvious,accounting for 43.3%of the ratio.The swing peaks of pyrrole ring and pyridine ring are mainly concentrated at 1027~1455 cm-1.The vibration peak of pyridine ring in-plane is mainly concentrated at 1008~1027 cm-1,and the swing peaks of pyridine ring out-of-plane are below 800 cm-1.The maximum absorption peak of UV spectrum is located at 173.46571 nm,which is mainly formed by the transition from ground state S0 to excited state S5,S6,S10,S11,S12,S9,S13 and S14.Among them,the transition from ground state S0 to excited state S11 has the greatest contribution,and the oscillator strength of other excited state transition is less than 0.03,which is forbidden transition.
作者
钟玉洁
陆利敏
李佳会
王婷
余娇
于建成
唐延林
ZHONG Yu-Jie;LU Li-Min;LI Jia-Hui;WANG Ting;YU Jiao;YU Jian-Cheng;TANG Yan-Lin(College of Physics, Guizhou University, Guiyang 550025, China)
出处
《原子与分子物理学报》
CAS
北大核心
2020年第2期157-162,共6页
Journal of Atomic and Molecular Physics
基金
国家自然科学基金(11164004)
贵州省光子科学与技术创新人才团队(20154017)
黔教合KY字【2016】215,贵州大学SRT项目。
关键词
尼古丁
密度泛函理论
前线轨道
红外光谱
紫外光谱
Nicotine
Density functional theory
Frontier orbit
Infrared spectrum(IR)
UV spectrum
