表面增强拉曼光谱研究胞嘧啶在银胶上的吸附行为

发布时间：2018-02-14 03:20

本文关键词： 胞嘧啶表面增强拉曼光谱吸附行为 DFT　出处：《发光学报》2017年04期 　论文类型：期刊论文

【摘要】：为探讨胞嘧啶(Cytosine,Cy)在基底银表面的吸附特性和规律,采用表面增强拉曼散射(SERS)光谱对其吸附行为进行分析,并结合量子化学密度泛函理论(DFT)/B3LYP计算方法对Cy分子的常规拉曼光谱(NRS)及Cy与Ag团簇吸附的SERS光谱进行计算,与测定结果进行比对且对其拉曼峰进行系统指认及归属,理论计算结合实测值探讨了Cy在基底Ag上的增强效应和吸附行为。考察了Cy分子在Ag纳米粒子上的不同吸附时间、浓度、pH等条件对SERS光谱的影响及优化,发现pH影响最大,在中性和强碱性条件下的增强效应明显优于酸性。Cy分子存在2种不同的异构体和3种不同的存在形态,并随酸度变化相互转化而达动态平衡。基于Cy在不同pH时的形态分布和相应的SERS变化规律,结合DFT算得的Cy分子中的电荷分布及在银基底表面的吸附机制,详细探讨了酸碱对Cy分子的SRES光谱影响的内因和吸附机理,指出在中性和弱碱性时,是Cy中的N3和O与Ag形成配位吸附;在pH大于11时,N与Ag形成配位吸附,而O与Ag形成共价吸附。
[Abstract]:In order to study the adsorption characteristics and regularity of cytosine cytosine cytosine on the surface of silver substrate, the adsorption behavior of cytosine cytosine cytosine on silver substrate was analyzed by surface enhanced Raman scattering (SERS) spectroscopy. The conventional Raman spectra of Cy and the SERS spectra of Cy adsorbed on Ag clusters were calculated by using DFT / B3LYP method of density functional theory of quantum chemistry. The results were compared with the measured results and the Raman peaks were systematically identified and assigned. The enhancement effect and adsorption behavior of Cy on Ag substrate were studied by theoretical calculation and experimental data. The influence and optimization of Cy molecules on SERS spectra were investigated under different adsorption time, concentration and pH of Cy molecules on Ag nanoparticles. The results showed that pH had the greatest influence on the SERS spectra. The enhancement effect at neutral and strong alkalinity is obviously superior to that of acid. Cy molecule with two different isomers and three different forms. Based on the speciation distribution of Cy at different pH and the corresponding law of SERS change, the charge distribution in Cy molecule and the adsorption mechanism on the surface of silver substrate were calculated by DFT. The internal cause and adsorption mechanism of the influence of acid and base on the SRES spectrum of Cy molecule are discussed in detail. It is pointed out that in neutral and weak alkalinity, N _ 3 and O in C _ y form coordination adsorption with Ag, and at pH > 11:00, N forms coordination adsorption with Ag. While O and Ag form covalent adsorption.
【作者单位】：浙江工业大学化学工程学院绿色化学合成技术国家重点实验室培育基地;
【基金】：浙江省自然科学基金(LQ17B050002) 浙江省公益性技术应用研究(分析测试)计划(2015C37068)资助项目~~
【分类号】：O657.37;O647.3

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