摘要
采用密度泛函B3LYP方法,在6-311+g(d)基组水平上研究了不同外电场对直线型分子N_(2)O的基态结构、偶极矩、轨道能级、红外和拉曼光谱特性的影响,并采用杂化CIS方法研究了N_(2)O分子在外电场作用下前9个激发态的激发特性.结果表明:外电场导致分子键长变化,但并没有改变分子的直线特征,偶极矩和分子总能量随外电场的增加先减小后增大,而能隙随外电场的增加先增大后减小,外电场的增加使LUMO(lowest unoccupied molecular orbital)组成由π^(*)轨道变为σ^(*)轨道,外电场使红外光谱发生移动,峰的强度增强或减弱.外电场的增加显著影响了N_(2)O分子的激发特性.激发能、激发波长受外电场影响发生了变化,同时,振子强度受外电场影响明显,禁阻跃迁变为可允许的跃迁,允许的跃迁在电场作用下变为禁阻跃迁或者跃迁变弱.紫外光谱在电场的作用下吸收峰发生了明显的移动,而且有新的吸收峰产生.
The B3LYP method of density functional theory(DFT)at 6-311+g(d)basis set level is used to study the influences of different external electric fields on the ground state structure,dipole moment,orbital energy level,infrared and Raman spectra of linear molecule N_(2)O.On the basis of this,the excitation characteristics of the first nine excited states of N_(2)O under external electric field were studied by single-exciation configuration interation(CIS)method.The results show that the external electric field leads to the change of molecular bond lengths,but does not change the linear characteristics of the molecule.The dipole moment and total molecular energy first decrease and then increase with the increase of the external electric field,while the energy gap first increases and then decreases with the increase of the external electric field.The increase of the external electric field makes the LUMO(lowest unoccupied molecular orbital)composition change fromπ^(*)orbital toσ^(*)orbital.The external electric field makes the infrared spectral frequency shift and the intensity of the peak increase or decrease.The increase of external electric field significantly affects the excitation properties of N_(2)O molecule.At the same time,the oscillator strength is obviously affected by the external electric field,and the forbidden transition becomes the allowed transition,and the allowed transition becomes the forbidden transition or the transition becomes weak under the action of the electric field.Under the action of electric field,the absorption peak of UV spectrum shifts obviously,and a new absorption peak appears.
作者
梁冬梅
荆涛
黄意
邓明森
LIANG Dong-Mei;JING Tao;HUANG Yi;DENG Ming-Sen(School of Science,Kaili University,Kaili 556011,China;School of Physics and Electronic Science,Guizhou Normal University,Guiyang 550018,China)
出处
《原子与分子物理学报》
CAS
北大核心
2022年第2期33-41,共9页
Journal of Atomic and Molecular Physics
基金
国家自然科学基金(11764024)
凯里学院博士专项基金(BS201601)
贵州省教育厅青年科技人才成长项目(黔教合KY字[2019]185)
凯里学院2017年度学术新苗培养及创新探索专项(黔科合平台人才[2017]5733-03)。
关键词
外电场
激发态
光谱
External electric field
Excited state
Spectrum
