哈龙1301分子在外电场中的光谱特征和解离特性

发布时间：2018-05-05 16:47

本文选题：哈龙 + DFT　；参考：《光谱学与光谱分析》2017年03期

【摘要】：哈龙1301(三氟溴甲烷)在太阳光辐射下解离生成破坏臭氧的溴自由基,严重破坏大气臭氧层,采用有效的措施对哈龙1301排放前进行降解很有必要。利用密度泛函理论(DFT)在B3LYP/6～311G++(d,p)水平上研究了外电场(0～0.03 a.u.)作用下哈龙1301分子的解离特性和光谱特征,包括总能量,键长,电偶极矩,LUMO-HOMO能隙,红外光谱以及解离势能面等。计算结果表明,在C——Br键连线Z方向上,外电场从0逐渐增加到0.03 a.u.时,分子体系能量逐渐减小,偶极矩在刚开始表现为减小然后单调增大,HOMO-LUMO能隙E_G呈现单调递减的趋势,C——Br键键长逐渐增大,C——F键键长逐渐减小。外电场对CF_3Br分子不同振动模式的红外光谱影响不同。在外电场作用逐渐增强下,解离特性表现为:CF_3Br分子的C——Br键方向扫描得到的势能曲线的束缚状态逐渐被消除,势垒逐渐变小最后消失。计算发现强度为0.03 a.u.的外电场足够使得CF_3Br分子发生C——Br键断裂而降解,该结果为保护环境而对哈龙进行电场降解提供重要参考依据。
[Abstract]:Halon 1301 (trifluorobromomethane) dissociates under solar light radiation to form bromine free radicals that destroy ozone and seriously destroy the atmospheric ozone layer. It is necessary to adopt effective measures to degrade halon 1301 before emission. The density functional theory (DFT) is used to study the external electric field at the B3LYP/6~311G level of 0.03 a.u. The dissociation characteristics and spectral characteristics of halon 1301 molecule under the action including total energy bond length electric dipole moment LUMO-Homo gap infrared spectrum and dissociation potential energy surface etc. The calculated results show that the external electric field increases gradually from 0 to 0.03 a.uin the Z direction of the C--Br bond. The energy of the molecular system decreases gradually, and the dipole moment decreases at the beginning and then monotonously increases the energy gap E _ G of HOMO-LUMO. The C ~ (-Br) bond length increases gradually and the C ~ (-F) bond length decreases gradually. The effects of external electric field on the infrared spectra of different vibrational modes of CF_3Br molecules are different. With the increasing of the external electric field, the dissociation characteristic is that the binding state of the potential energy curve obtained by the C--Br bond direction scanning of the w / CF3Br molecule is gradually eliminated, and the potential barrier becomes smaller and then disappears. The calculated strength is 0.03 a.u. The external electric field of CF_3Br is sufficient to break the C--Br bond and degrade the CF_3Br molecule. This result provides an important reference for environmental protection and the degradation of halons by electric field.
【作者单位】：南京信息工程大学物理与光电工程学院;江苏省大气环境与装备技术协同创新中心;皖南医学院弋矶山医院;Advanced
【基金】：国家自然科学基金项目(11304157,U1404112,11504175) 江苏省六大人才高峰高层次人才项目(2015-JNHB-011)资助
【分类号】：O561

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