本文選題：表面等離激元共振 + 密度泛函理論(DFT)�。� 參考：《西南大學(xué)》2017年碩士論文

【摘要】：近年來,基于等離激元增強(qiáng)的光催化反應(yīng)成為了研究熱點(diǎn)。金或者銀納米粒子在一定波長(zhǎng)的激發(fā)光照射下其表面的自由電子在外界光電場(chǎng)的擾動(dòng)下會(huì)發(fā)生集體振蕩。當(dāng)入射光電場(chǎng)的頻率與金屬納米結(jié)構(gòu)電子振蕩的固有頻率匹配時(shí)就會(huì)產(chǎn)生共振現(xiàn)象,這種現(xiàn)象稱為表面等離激元共振。表面等離激元共振因其獨(dú)特性質(zhì)而對(duì)表面化學(xué)具有多種促進(jìn)作用,因而等離激元增強(qiáng)表面催化反應(yīng)有望成為一種高效的太陽(yáng)能轉(zhuǎn)化途徑。大量的文獻(xiàn)報(bào)道了芳香族分子吸附在金屬表面或者金屬電極上,其拉曼信號(hào)會(huì)顯著增強(qiáng)。至今為止,人們就芳香族分子吸附在金屬表面后其拉曼信號(hào)增強(qiáng)的機(jī)理仍然缺乏全面理解。對(duì)于拉曼信號(hào)的增強(qiáng)機(jī)理,科學(xué)家們普遍持兩種觀點(diǎn):化學(xué)增強(qiáng)機(jī)理和電磁場(chǎng)增強(qiáng)機(jī)理。人們對(duì)于電磁增強(qiáng)機(jī)理研究的較為透徹,而對(duì)于化學(xué)增強(qiáng)機(jī)理局限于光驅(qū)電荷轉(zhuǎn)移機(jī)理而忽略了表面等離激元的化學(xué)效應(yīng)。因此本論文以表面等離激元的化學(xué)效應(yīng)為出發(fā)點(diǎn),從等離激元增強(qiáng)拉曼光譜(PERS)和等離激元增強(qiáng)化學(xué)反應(yīng)(PECR)兩個(gè)方面開展研究。相應(yīng)的研究?jī)?nèi)容和結(jié)果如下:(1)采用密度泛函理論(DFT)計(jì)算模擬PNA的常規(guī)拉曼光譜和表面拉曼光譜,并對(duì)其振動(dòng)模式進(jìn)行指認(rèn)。提出PNA分別在溶液中和空氣中的光誘導(dǎo)催化偶聯(lián)反應(yīng)合理的反應(yīng)路線并計(jì)算反應(yīng)微觀機(jī)理路徑上的各物質(zhì)。理論研究證實(shí)PNA在溶液中發(fā)生還原偶合反應(yīng)生成DAAB,在空氣中發(fā)生氧化偶合反應(yīng)生成DNAB。(2)利用SERS技術(shù)結(jié)合DFT研究對(duì)苯二胺以及對(duì)二硝基苯是否可以發(fā)生等離激元光聚合反應(yīng)。這部分工作包括DNB和PDA的常規(guī)拉曼譜和表面拉曼譜和對(duì)應(yīng)的實(shí)驗(yàn)譜圖以及相關(guān)的反應(yīng)機(jī)理。實(shí)驗(yàn)和理論證明DNB和PDA分別在溶液中和空氣中發(fā)生還原偶合和氧化偶合反應(yīng)生成對(duì)應(yīng)的N-N偶聯(lián)寡聚物。(3)采用密度泛函理論方法分別研究了在暗場(chǎng)和光照條件下偶氮苯和對(duì)苯乙烯在納米銀粒子作用下的反順異構(gòu)化反應(yīng)。我們計(jì)算了偶氮苯和對(duì)苯乙烯的反順異構(gòu)化反應(yīng)的反應(yīng)勢(shì)能曲線以及他們和金屬相互作用的光驅(qū)電荷轉(zhuǎn)移躍遷能和分子軌道圖。結(jié)果表明空穴氧化反式偶氮苯和對(duì)苯乙烯使其轉(zhuǎn)化成對(duì)應(yīng)的順式構(gòu)型是Ag NPs輔助偶氮苯以及對(duì)苯乙烯的反順異構(gòu)化最可能的方式。本課題工作不僅幫助我們弄清楚了目標(biāo)分子吸附在金屬表面后信號(hào)增強(qiáng)的原因而且還為我們獲得偶氮苯類化合物提供了一種新的綠色方法。此外,對(duì)于偶氮苯以及對(duì)苯乙烯的研究可以進(jìn)一步幫助我們將偶氮苯和對(duì)苯乙烯應(yīng)用于實(shí)際光學(xué)分子開關(guān)。
[Abstract]:In recent years, the photocatalytic reaction based on the enhancement of isophosphors has become a hot topic. The free electrons on the surface of gold or silver nanoparticles under the excitation light of a certain wavelength will oscillate collectively under the disturbance of the external photoelectric field. Resonance occurs when the frequency of the incident photoelectric field matches the natural frequency of the electron oscillation of the metal nanostructure. This phenomenon is called surface isoexciton resonance. Due to its unique properties, surface isoexciton resonance can promote surface chemistry. Therefore, it is expected that the surface catalytic reaction enhanced by isophosphors will become an efficient way of solar energy conversion. A large number of literatures have reported that the Raman signal of aromatic molecules adsorbed on metal surface or on metal electrode will be significantly enhanced. Up to now, there is still a lack of comprehensive understanding of the mechanism of Raman signal enhancement of aromatic molecules adsorbed on metal surface. Scientists generally hold two views on the enhancement mechanism of Raman signal: chemical enhancement mechanism and electromagnetic field enhancement mechanism. The study of electromagnetic enhancement mechanism is more thorough, while the chemical enhancement mechanism is limited to the charge transfer mechanism of optical drive and neglects the chemical effect of surface isoexcitators. Therefore, based on the chemical effect of surface isophosphors, this thesis studies on the two aspects of isophosphorus enhanced Raman spectroscopy (PERS) and isophoric enhanced chemical reaction (PECR). The corresponding research contents and results are as follows: (1) the conventional Raman spectra and surface Raman spectra of simulated PNA are calculated by density functional theory (DFT) and the vibrational modes are identified. A reasonable route for photo-induced coupling reaction of PNA in solution and in air was proposed, and the substances in the path of micro-mechanism of the reaction were calculated. It is proved that PNA can be synthesized by reductive coupling reaction in solution and oxidative coupling reaction in air to form DNAB.t2) the isobaric photopolymerization of p-phenylenediamine and p-dinitrobenzene can be studied by SERS and DFT. This work includes the conventional Raman spectra and surface Raman spectra of DNB and PDA, the corresponding experimental spectra and the related reaction mechanisms. Experimental and theoretical results show that DNB and PDA have reduced coupling and oxidative coupling reactions in solution and air respectively to form corresponding N-N coupling oligomers. (3) the density functional theory (DFT) method has been used to study the coupling under dark and light conditions, respectively. The transisomerization of azobenzene and p-styrene under the action of silver nanoparticles. We have calculated the potential energy curves of the transisomerization of azobenzene and styrene, the charge transfer transition energy and molecular orbital diagram of their interaction with metal. The results show that hole oxidation of trans-azobenzene and p-styrene into the corresponding cis-configuration is the most likely way of Ag NPs assisted azobenzene and p-styrene trans-cis-isomerization. This work not only helps us to find out the cause of signal enhancement of target molecules adsorbed on metal surface, but also provides us a new green method for obtaining azobenzene compounds. In addition, the study of azobenzene and p-styrene can further help us to apply azobenzene and p-styrene to practical optical molecular switches.
【學(xué)位授予單位】：西南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O621.254

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相關(guān)期刊論文 前2條

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2 趙劉斌;黃逸凡;吳德印;任斌;;對(duì)氨基苯硫酚分子的表面增強(qiáng)拉曼光譜及等離激元光催化反應(yīng)[J];化學(xué)學(xué)報(bào);2014年11期

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本文編號(hào)：1805061