基于外电场作用氟氯碳酰的光谱特性和解离特性

Spectrum characteristics and dissociation characteristics of carbonyl chloride fluoride under external electric field

采用密度泛函方法(DFT)在B3LYP/6-31G(d)水平上优化计算了在不同外电场作用下氟氯碳酰分子的物理性质,包括键长、键角、分子体系总能量、偶极矩、能隙、红外光谱、拉曼光谱以及解离特性.研究表明在外电场(-0.02—0.07 a.u.)作用下,氟氯碳酰分子结构有明显的变化,随着外电场的增强,分子C-O键长、C-Cl键长逐渐增大,C-F键长逐渐减小,分子体系总能量、能隙先增大后减小,偶极矩先减小后增大;分子红外光谱的O p-deform、CCl stretch(str)、CF str振动发生了蓝移,CO str振动发生了红移,CO deform振动先红移后蓝移,分子拉曼光谱的O p-deform、CCl str、CF str、CO str振动移动情况与红外光谱相同,当外电场强度为0.03 a.u.时,分子C-Cl势垒消失,分子发生解离,当外电场强度为-0.005 a.u.时,分子两个键断裂,发生逐步解离.研究工作为进一步研究氟氯碳酰分子的解离特性及臭氧层的保护提供理论依据.

Density functional theory(DFT)is used to optimize the physical properties of carbonyl chloride fluoride molecules under different external electric fields at the B3LYP/6-31G(d)level,including bond length,bond angle,total energy of the molecular system,dipole moment,energy gap,infrared spectrum,Raman spectrum and dissociation characteristics.Studies have shown that under the action of an external electric field(-0.02—0.07 a.u.),the molecular structure of carbonyl chloride fluoride changes significantly.With the enhancement of the external electric field,the molecular C-O bond length and C-Cl bond length gradually increase,and the C-F bond length gradually decrease,the total energy and energy gap of the molecular system first increase and then decrease,the dipole moment first decreases and then increases;the O p-deform,CCl str,and CF str vibrations of the molecular infrared spectrum have a blue shift,and for the CO str vibration,a red shift occurs.The CO deform vibration is first red shifts and then blue shifts.The Op-deform,CCl str,CF str,and CO str vibration movements of the molecular Raman spectrum are the same as to those of the infrared spectrum.When the external electric field intensity is 0.03 a.u.,the C-Cl bond barrier disappears and the molecules dissociate.When the intensity of the external electric field is-0.005a.u.,the two bonds of the molecule are broken and gradually dissociated.This will provide a theoretical basis for further research on the dissociation characteristics of carbonyl chloride fluoride molecules and the protection of the ozone layer.