Quantum Mechanical Calculations of Vibrational Sum-Frequency-Generation (SFG) Spectra of Cellulose: Dependence of the CH and OH Peak Intensity on the Polarity of Cellulose Chains within the SFG Coherence Domain.
Quantum Mechanical Calculations of Vibrational Sum-Frequency-Generation (SFG) Spectra of Cellulose: Dependence of the CH and OH Peak Intensity on the Polarity of Cellulose Chains within the SFG Coherence Domain.
复制标题
纤维素振动和频发生 (SFG) 谱的量子力学计算：CH 和 OH 峰强度对 SFG 相干域内纤维素链极性的依赖性。
DOI：
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发表时间：
2017
影响因子：
5.7
通讯作者：
Seong H. Kim
中科院分区：
文献类型：
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作者：
Christopher M. Lee;Xing Chen;Philip A Weiss;L. Jensen;Seong H. Kim
振动和频发生（SFG）光谱能够选择性地检测散布在无定形聚合物基质中的结晶生物聚合物。然而，光谱解释是困难的，由于缺乏知识的结晶段的空间排列如何影响SFG光谱特征。在这里，我们报告的含时密度泛函理论（TD-DFT）计算的纤维素微晶密切接触的两个不同的极性：平行与反平行。TD-DFT计算表明，CH/OH强度比是非常敏感的极性的微晶包装。超极化率张量（βabc）的理论计算清楚地显示了SFG强度对SFG相干长度内微晶堆积极性的依赖性，这为解释生物系统中天然纤维素的经验观察SFG特征提供了基础。
Vibrational sum-frequency-generation (SFG) spectroscopy is capable of selectively detecting crystalline biopolymers interspersed in amorphous polymer matrices. However, the spectral interpretation is difficult due to the lack of knowledge on how spatial arrangements of crystalline segments influence SFG spectra features. Here we report time-dependent density functional theory (TD-DFT) calculations of cellulose crystallites in intimate contact with two different polarities: parallel versus antiparallel. TD-DFT calculations reveal that the CH/OH intensity ratio is very sensitive to the polarity of the crystallite packing. Theoretical calculations of hyperpolarizability tensors (βabc) clearly show the dependence of SFG intensities on the polarity of crystallite packing within the SFG coherence length, which provides the basis for interpretation of the empirically observed SFG features of native cellulose in biological systems.