外电场下氨分子光谱与激发特性研究  

Spectrum and excitation properties of the ammonia under external electric field

作　　者：杨涛[1,2] 邓俊 王俊[1,2] 闫蓓蕾 吉俊懿 YANG Tao;DENG Jun;WANG Jun;YAN Bei-Lei;JI Jun-Yi(School of Biological and Chemical Engineering,Panzhihua University,Panzhihua 617000,China;Material Corrosion and Protection Key Laboratory of Sichuan province,Sichuan University of Science and Engineering,Zigong 643000,China;College of Chemical Engineering,Sichuan University,Chengdu 610044,China)

机构地区：[1]攀枝花学院生物与化学工程学院,攀枝花617100 [2]四川轻化工大学材料腐蚀与防护四川省重点实验室,自贡643000 [3]四川大学化学工程学院,成都610044

出　　处：《原子与分子物理学报》2023年第4期1-8,共8页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(21776187);攀枝花市2020年度市级指导性科技计划项目(2020ZD-S-30);四川轻化工大学材料腐蚀与防护四川省重点实验室开放基金(2019CL20)。

摘　　要：利用筛选的B3PW91密度泛函方法在CC-PVQZ基组下优化出氨分子的基态稳定构型,并考察了不同外电场对NH_(3)分子的特性及红外光谱(IR)的影响,在此基础上利用TD-DFT考察了不同外电场对NH_(3)分子前9个激发态的影响.结果表明:电场由0 a.u.增加至0.04 a.u.时,NH_(3)的构型参数与电场强度有明显的依赖关系;总能量(E_(T))呈下降的趋势;偶极矩(μ)呈增加的趋势;最高占据分子轨道(HOMO)的能级呈降低的趋势,最低空分子轨道(LUMO)的能级呈增加的趋势;能隙(E_(G))呈增加的趋势,即外电场会影响NH_(3)参与化学反应的能力;IR在电场考察范围内的特征峰位置及强度均会受到电场的影响,即可利用电场对分子的IR进行调控,从而便于对相关谱图信息的捕捉;外电场对NH_(3)分子的激发能及振子强度均有影响,因此,可以利用外电场来调控NH_(3)的激发特性.This work focuses on the effect of external electric fields on NH_(3).In order to get more credible results,the density functional theory(DFT)B3PW91 method is chosen to achieve the following computational work.The ground states of NH_(3)in different external electric fields ranging from 0 a.u.to 0.04 a.u.are optimized by B3PW91 method with CC-PVQZ basis sets.The molecule conformation parameters and infrared spectra(IR)of NH_(3)under different external electric fields are calculated,respectively.Furthermore,the effects of different external electric fields on the excited states of NH_(3)are investigated by TD-DFT.The molecule conformation parameters and charge distribution of NH_(3)strongly depend on the external electric field.The total energy(E^(T))decreases with the external electric field.In contrary,the dipole moment(μ)keeps increasing over investigative external electric field.The energy level of the lowest unoccupied molecular orbital(LUMO)increases through the variation of the external electric field,but the energy level of the highest occupied molecular orbital(HOMO)is proved to decrease as the change of external electric field.The energy gap(E_(G))is found to increase with the external electric field.Through investigating the E G of NH_(3),it has been found that the external electric fields have a big impact on the chemical reactivity of NH_(3).Both location and intensity of IR characteristic peaks of NH_(3)also can be affected by the external electric field.The external electric field can be used to regulate the IR of molecule,and then it is convenient to capture the spectral information.In addition,both excitation energy and oscillator strength of NH_(3)can be easily influenced by the external electric fleld.Therefore,the excitation properties of NH_(3)can be regulated by the external electric field.

关 键 词：NH_(3) 外电场 光谱性质 激发特性 

分 类 号：O56[理学—原子与分子物理]