| 基于量子化学的太赫兹吸收峰形成机理解析 |
| Analysis of the Formation Mechanism of Terahertz Absorption Peaks Based on Quantum Chemistry |
| 投稿时间：2024-11-13 修订日期：2024-11-29 |
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| 中文摘要: |
| 本文以苯甲酸和山梨酸为对象,利用太赫兹时域光谱系统(THz-TDS)获取其单质与混合样片在0.5~2.2 THz范围内的时域光谱,实现对苯甲酸和山梨酸两种添加剂的定性鉴别。针对混合样片太赫兹吸收谱中的特征吸收峰偏移和缺失等异常吸收现象,进一步探讨太赫兹特征吸收峰的形成机理,自行构建剑桥晶体数据中心未收录的苯甲酸-山梨酸混合物二聚体团簇模型,结合密度泛函理论完成构型的结构优化与频率计算。通过势能分布(PED)进行了吸收峰的振动模式匹配,并结合基于Hirshfeld原子空间划分的独立梯度模型(IGMH)和相互作用区域指示函数(IRI)进行分子间相互作用的可视化分析。研究表明,混合物特定吸收峰源于分子间氢键作用和分子内化学键作用引起的集体振动模式。本研究为苯甲酸和山梨酸在太赫兹频段的定性鉴别及特征吸收峰的机理分析提供了实验和理论支持,提升了混合体系光谱定量分析的精度,并为晶体结构表征提供了一种新的方法。 |
| 英文摘要: |
| This study focuses on benzoic acid and sorbic acid, using a terahertz time-domain spectroscopy (THz-TDS) system to measure the spectral data of their pure and mixed samples in the 0.5–2.2 THz range. Through data preprocessing, terahertz absorption spectra were obtained, allowing for the qualitative identification of these two additives. To explore the formation mechanism of terahertz characteristic absorption peaks, the study further analyzed abnormal absorption phenomena in the experimental spectra of mixed samples, such as shifts and missing characteristic peaks. A benzoic acid-sorbic acid dimer cluster model, not included in the Cambridge Crystallographic Data Centre (CCDC), was constructed. Structural optimization and frequency calculations were performed using density functional theory (DFT). The vibration modes of the absorption peaks were analyzed through potential energy distribution, and intermolecular interactions were visualized using the Independent Gradient Model based on Hirshfeld partitioning (IGMH) and the Interaction Region Indicator (IRI) function. The results show that specific absorption peaks in the mixture are attributed to collective vibrational modes arising from intermolecular hydrogen bonding and intramolecular chemical bonding interactions. This study provides experimental and theoretical support for the qualitative identification of benzoic acid and sorbic acid in the terahertz range and the analysis of the formation mechanism of characteristic absorption peaks. It also enhances the accuracy of quantitative spectral analysis in mixed systems and introduces a new method for characterizing crystal structures. |
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| 中文关键词: 太赫兹时域光谱 机理解析 食品添加剂 团簇构型 特征吸收峰 |
| 英文关键词:terahertz time-domain spectroscopy mechanism analysis food additives cluster configuration characteristic absorption peaks |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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