本文關(guān)鍵詞：維生素的太赫茲光譜數(shù)據(jù)庫研究　出處：《南京林業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 傅里葉變換紅外光譜 維生素 量子化學(xué)計算 密度泛函理論 分子振動模式

【摘要】：太赫茲(THz)波是屬于遠紅外波段的電磁頻譜,位于微波和中紅外波之間,有時被稱為遠紅外波,是指頻率在0.1~10THz范圍內(nèi)的電磁波(1THz=1012Hz)。THz輻射具有低能性,一般不會對生物分子的結(jié)構(gòu)與活性造成損傷,此外還具有穿透性、指紋性等特征,使THz技術(shù)廣泛應(yīng)用于無損檢測領(lǐng)域。傅里葉變換紅外光譜技術(shù)FTIR(Fourier Transform Infrared Spectroscopy)是常見的太赫茲寬頻帶測量方法,用于測量各類材料和生物分子的光學(xué)特性,已被證實在低頻段具有和太赫茲時域光譜儀(TDS)類似的靈敏度。分子的THz光譜包括分子內(nèi)和分子間的共同作用,前者包括分子內(nèi)基團的搖擺和轉(zhuǎn)動、非共價鍵作用等,后者包括氫鍵作用、弱靜電力以及范德華力等,同時受到分子與環(huán)境的相互作用力影響。研究證明除了太赫茲頻段,遠紅外高頻段、中紅外、近紅外頻段的頻譜對于研究生物分子的振動和轉(zhuǎn)動特性也具有重要的指導(dǎo)意義。本文利用傅里葉變換紅外光譜技術(shù),對幾種維生素樣品進行了THz光譜研究,同時,嘗試用Gaussian軟件中的密度泛函理論(DFT)對實驗結(jié)果得到的指紋譜的形成機制進行理論解釋。本工作的研究內(nèi)容主要包括實驗測量和理論解析兩方面,主要內(nèi)容包括:1、通過傅里葉變換紅外光譜系統(tǒng),對吡哆素、生物素、核黃素、葉酸、維生素K2這幾種常見維生素在太赫茲寬頻段的光譜特性進行了研究。詳細分析了維生素樣品與聚乙烯粉末不同比例混合時的吸收光譜,將所得光譜進行比較,最后確定詳實可靠的光譜圖。結(jié)果表明它們在其有效波段內(nèi)的光譜有很大差異,表現(xiàn)為吸收峰的個數(shù)、位置的差異。實驗研究結(jié)果可用于建立維生素太赫茲光譜指紋數(shù)據(jù)庫,也為后面章節(jié)理論解析維生素太赫茲光譜提供了依據(jù)。2、采用密度泛函理論(DFT)對葉酸和維生素K2的單分子模型進行模擬計算,并對其振動模式進行了指認。研究表明對于大部分固體維生素,它們的單分子模型模擬出的吸收峰的位置與實驗存在一定差異,主要是由理論模擬采用的單分子模型與實驗晶體樣品結(jié)構(gòu)的差異造成的。而核黃素單分子較晶胞分子的理論模擬,與實驗測試結(jié)果一致性好,證明核黃素的吸收峰大都來自于分子內(nèi)基團的振動。3、為了克服單分子模型模擬晶體維生素的局限性,分別對生物素和吡哆素的晶胞結(jié)構(gòu)進行模擬計算,重點分析了生物素和吡哆素的單分子、二分子、三分子、以及晶胞分子的太赫茲光譜,闡明了分子內(nèi)和分子間相互作用力的振動和轉(zhuǎn)動機制,并對光譜吸收峰的振動模式進行了指認。
[Abstract]:Terahertz (THz) wave is a kind of electromagnetic spectrum in the far infrared band. It is located between the microwave and the middle infrared wave and is sometimes called the far infrared wave. The electromagnetic wave with frequency of 0.1 ~ 10THz has low energy and does not damage the structure and activity of biomolecules. In addition, it also has the characteristics of penetrability, fingerprint and so on. THz technology is widely used in the field of nondestructive testing. Fourier transform Infrared Spectroscopy (FTIR). Fourier Transform Infrared spectroscopyis a common terahertz broadband measurement method. Used to measure the optical properties of all kinds of materials and biomolecules. It has been proved that TDs have similar sensitivity to TDs at low frequency. The THz spectra of molecules include intramolecular and intermolecular interaction, the former includes the rocking and rotation of intramolecular groups. Non-covalent bond interactions, such as hydrogen bonding, weak electrostatic force and van der Waals force, are also affected by the interaction between molecules and the environment. It has been proved that in addition to terahertz band, far-infrared high frequency band, mid-infrared. The near infrared spectrum is also of great significance for studying the vibration and rotation characteristics of biomolecules. In this paper, the THz spectra of several vitamin samples are studied by Fourier transform infrared spectroscopy (FTIR). At the same time. Using density functional theory in Gaussian software. The formation mechanism of fingerprint spectrum obtained from the experimental results is explained theoretically. The research contents of this work mainly include two aspects: experimental measurement and theoretical analysis. The main contents include: 1, through Fourier transform infrared spectroscopy system, pyridoxine, biotin, riboflavin, folic acid. The spectral characteristics of vitamin K2 were studied in terahertz wide band. The absorption spectra of vitamin K2 mixed with polyethylene powder were analyzed in detail, and the spectra were compared. Finally, the detailed and reliable spectra are determined. The results show that their spectra in the effective band are very different, which is shown by the number of absorption peaks. The experimental results can be used to establish the vitamin terahertz spectrum fingerprint database and provide a basis for the theoretical analysis of vitamin terahertz spectrum in the following chapters. The single molecular model of folic acid and vitamin K2 was simulated by density functional theory (DFT) and its vibration mode was identified. The position of the absorption peak simulated by their monolayer model is different from that of the experiment. It is mainly caused by the difference between the monolayer model used in theoretical simulation and the structure of experimental crystal sample, while the riboflavin monolayer is in good agreement with the experimental results compared with the theoretical simulation of unit cell molecule. It is proved that the absorption peaks of riboflavin mainly come from the vibration of intramolecular group. In order to overcome the limitation of single molecular model simulating crystal vitamins, the unit cell structures of biotinyl and pyridoxine were simulated and calculated respectively. The terahertz spectra of single molecule, two molecule, three molecule and unit cell molecule of biotin and pyridoxine were analyzed, and the vibration and rotation mechanism of intramolecular and intermolecular interaction forces were elucidated. The vibrational modes of the spectral absorption peaks are also identified.
【學(xué)位授予單位】：南京林業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O441.4;O433

【引證文獻】

相關(guān)期刊論文 前1條

1 蔡蒙;王芳;;太赫茲光譜技術(shù)在氨基酸鑒定中的應(yīng)用[J];電子世界;2016年13期

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本文編號：1403537