基于色散校正的密度泛函理论的食品添加剂太赫兹光谱研究  

Investigation on Terahertz Spectroscopy of Food Additives Based on Dispersion-Correction Functional Theory

作　　者：李天莹 李春[1] 章龙 马卿效 蒋玲[1] LI Tian-ying;LI Chun;ZHANG Long;MA Qing-xiao;JIANG Ling(College of Information Science and Technology,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学信息科学技术学院,江苏南京210037

出　　处：《光谱学与光谱分析》2021年第1期100-104,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(31200541);江苏省自然科学基金项目(BK20161526)资助。

摘　　要：食品添加剂违规使用或滥用会对身体健康产生严重危害,相比于传统检测方法,太赫兹光谱技术具有检测周期短、准确率高等优势,被广泛应用于食品添加剂检测领域,但对其缺乏深入的理论分析。主要致力于根据晶体结构特征改进传统计算方法,提高食品添加剂模拟光谱预测精度并评估不同模型的计算性能。选取了三种富含氢键的食品添加剂,即苯甲酸、山梨酸和木糖醇,实验采用太赫兹时域光谱仪,理论计算采用CRYSTAL14软件包计算周期性晶体结构。鉴于富含氢键的体系中伦敦色散作用力不可忽略,在传统的Becke-3-Le e-Yang-Par(B3LYP)泛函和Perdew-Burke-Ernzerhof(PBE)泛函的基础上添加了伦敦色散校正系数,构建了B3LYP-D和PBE-D模型。计算得到吸收峰位平均绝对误差(AAE)分别为苯甲酸0.073(B3LYP-D)、0.096(PBE-D),山梨酸0.039(B3LYP-D)、0.047(PBE-D),木糖醇0.023(B3LYP-D)、0.087(PBE-D),相比于色散校正前的模型,AAE降低了0.03~0.1。对比了B3LYP-D和PBE-D模型的计算时长,B3LYP-D泛函耗时均为PBE-D泛函的二倍以上。结果表明,经色散校正后的模型适用于富含氢键的系统,能够提高模拟光谱预测精度,其中B3LYP-D模型预测精度更高但较为耗时,PBE-D泛函预测精度略低于B3LYP-D模型,但计算速度更快。振动来源分析表明,三种食品添加剂的振动模式均以晶格整体的平移和旋转为主,分子内的振动贡献较小。研究提出的色散校正模型对于其他类似体系的理论研究具有重要的参考价值。Illegal use or abuse of food additives candamage human health.Terahertz(THz)spectroscopy was widely used for food additives detection with fast and accurate etc.advantages,but lacked in-depth theoretical analysis.This paperexplores to improve traditional methods to produce higher quality simulation spectra,and evaluate different models.THz spectra of sorbic acid,benzoic acid and xylitol were obtained by terahertz time-domain spectroscopy.Simulations were performed using CRYSTAL14 software to calculate the periodic crystals.Considering that dispersion force cannot be ignored in hydrogen-bonded systems,the dispersion correction term was used to augment the traditional functionals to construct the B3 LYP-D and PBE-D models.The average absolute error(AAE)of benzoic acid absorption peak positions was 0.073 for B3 LYP-D model,0.096 for PBE-D model.For sorbic acid,AAE was 0.039 and 0.047,xylitol 0.023 and 0.087.The values of AAE were decreased by 0.03~0.1 compared with primitive functionals.The computation time of B3 LYP-D model was more than twice of PBE-D model.Results showed that dispersion-corrected models can produce higher quality simulation spectra for hydrogen-bonded systems.The B3 LYP-D model holds higher accuracy but is more time-consuming;the PBE-D model provides comparable accuracy to B3 LYP-D model with much higher simulation speed.The spectral features were as signed as primarily lattice translations and rotations with lesser intramolecular torsions.The dispersion-corrected model proposed in this paper has important reference value for the theoretical research of other similar systems.

关 键 词：太赫兹光谱 食品添加剂 周期性晶体结构 氢键系统 色散校正 

分 类 号：O433.5[机械工程—光学工程]