CF~-、CN分子的光谱特性研究
发布时间:2018-03-11 10:26
本文选题:CF~-负离子 切入点:CN自由基 出处:《太原科技大学》2017年硕士论文 论文类型:学位论文
【摘要】:碳元素是人类最早接触和利用的元素之一,在自然界分布非常广泛。碳化物分子包含许多重要的无机物分子(如CO_2、CH_4、CN等),并且是构成生命体的主要有机物分子,与我们的生活息息相关。而含碳双原子分子作为最简单的碳化物分子,更是受到了研究人员的广泛关注。光谱是物质的“指纹”,是对分子特性及内部结构的最直接反应。因此,不论是通过理论计算光谱参数还是通过实验光谱测量来研究分子的能级分布及光谱特性一直是学术界的热门课题。本论文对含碳双原子分子CF~-进行了量化计算,同时采用激光诱导击穿光谱技术(LIBS)对CN自由基的振-转跃迁谱线进行了测量。理论计算方面,我们采用MOLPRO量化计算软件对CF~-负离子做了从头计算。利用高精度的内收缩多参考组态相互作用方法(icMRCI)基于相关一致基组aug-cc-pV5Z在0.8到7?的范围内计算了CF~-负离子两个最低解离极限C(~3P_2)+F-(~1S_0)和C(~1D_2)+F-(~1S_0)对应的5个Λ-S态(X3Σ-,a1Δ,b1Σ+,A~3П和c1П)的势能曲线。计算中考虑了标量相对论修正和Davidson修正使得计算结果更加可靠。根据?-S态的势能曲线,求解径向薛定谔方程得到了各电子态振转能级,并拟合获得了这些电子态的光谱常数(Te,Re,ωe,ωeχe,Be,αe,De)。此外,我们对CF~-负离子5个?-S态的电偶极矩曲线进行了计算,分析了电子态的组态变化对电偶极矩的影响。另外,我们计算了CF~-负离子A~3Π X3Σ-的跃迁偶极矩并采用LEVEL程序解得了Franck-Condon因子,分析了这两个电子态之间的跃迁特性,获得了A~3П的5个最低振动能级的辐射寿命τ,并给出了振子强度f00。最后,对CF~-负离子A~3П态的预解离机理进行了研究,并计算了A~3П态几个高振动能级的解离寿命τd。实验方面,我们采用LIBS测量了CN自由基B~2Σ~+ X~2Σ~+系统的振转跃迁谱线。用Nd:YAG调Q脉冲激光器在空气中对石墨样品进行激光烧蚀,激光被聚焦到样品靶点0.5mm以上位置,以期同时电离石墨样品中的C原子及空气中的N2分子形成高温高能等离子体团。然后等离子体团中C原子跟N原子自由组合成CN自由基并自发辐射到低态,我们再通过光谱仪对其辐射的荧光进行采集,得到了CN自由基B~2Σ~+ X~2Σ~+的振动跃迁谱线,并用LIFBASE软件拟合出了X~2Σ~+的振动及转动温度,分别为4600K和4400K。
[Abstract]:Carbon is one of the earliest elements in human contact and utilization, which is widely distributed in nature. Carbides contain many important inorganic molecules (such as CO2C, CH4C4CN, etc.) and they are the main organic molecules that make up living organisms. Carbon diatomic molecules, as the simplest carbides, have attracted much attention from researchers. The spectrum is the "fingerprint" of matter and the most direct reaction to the molecular properties and internal structure. It has always been a hot topic in academic circles to study the energy level distribution and spectral characteristics of molecules whether by theoretical calculation of spectral parameters or by means of experimental spectral measurements. In this paper, the quantitative calculation of carbon-containing diatomic molecules CF- has been carried out. Laser induced breakdown spectroscopy (LIBS) is also used to measure the vibration-transpression spectra of CN radicals. We have done ab initio calculation of CFC-negative ions by using MOLPRO quantitative calculation software. Using the high-precision internal contraction multi-reference configuration interaction method, the aug-cc-pV5Z is 0.8 to 7 based on the correlation consistent basis set. The potential energy curves corresponding to the two lowest dissociation limits C ~ (3 P _ 2) (C ~ (3) P _ (2)) F _ D _ (0) and C _ (1) D _ (2) C _ (1) C _ (1) C _ (1) and C _ 1) have been calculated in the range of C ~ (2 +) and C _ (1). The calculation results are more reliable by taking into account the relativistic correction of the scalar and the Davidson's amendment. According to the results of the calculation, we have calculated the potential energy curves of the X ~ (3) 危 ~ (-1) 螖 B ~ (1) 危 A ~ (3) and c _ (1). The vibrational energy levels of each electronic state are obtained by solving the radial Schrodinger equation, and the spectral constants of these electronic states are obtained by fitting. The electric dipole moment curve of the -S state is calculated, and the influence of the configuration of the electronic state on the electric dipole moment is analyzed. In addition, we calculate the transition dipole moment of the CF-negative ion An 3 蟺 X 3 危-and obtain the Franck-Condon factor by using LEVEL program. The transition characteristics between the two electronic states are analyzed, and the radiation lifetime 蟿 of the five lowest vibrational levels of An 3 O is obtained, and the oscillator strength f 00. finally, the predissociation mechanism of the CF-negative ion Af3 state is studied. The dissociation lifetime 蟿 d of several high vibrational energy levels in the Ani3 state has been calculated. In the experimental aspect, we have measured the vibrational transition lines of the CN free radical B ~ (2 危 ~) ~ (X _ (2) O ~ (2) 危 ~ ~ (2)) system by using LIBS. The Nd:YAG Q-switched pulse laser has been used to ablate the graphite sample in the air. The laser is focused on the sample target above 0.5 mm, It is hoped that the C atom in the graphite sample and the N 2 molecule in the air will be ionized simultaneously to form a high-temperature high-energy plasma cluster, and then the C atom and the N atom in the plasma cluster will combine freely to form CN radical and spontaneously radiate to a low state. The fluorescence spectra of the CN free radical B _ (2) 危 ~ (?) X _ (2) O ~ (2) ~ ~ were obtained by means of spectrometer, and the vibration and rotation temperatures of X _ (2) 危 ~ ~ were fitted by LIFBASE software, which were 4600K and 4400K, respectively.
【学位授予单位】:太原科技大学
【学位级别】:硕士
【学位授予年份】:2017
【分类号】:O561.3
【参考文献】
相关期刊论文 前6条
1 周锐;李传亮;和小虎;邱选兵;孟慧艳;李亚超;赖云忠;魏计林;邓伦华;;基于ab initio计算的CF~-离子低激发态光谱性质研究[J];物理学报;2017年02期
2 邢伟;刘慧;施德恒;孙金锋;朱遵略;;icMRCI+Q理论研究CF离子12个-S态和23个?态的光谱性质[J];物理学报;2016年03期
3 邢伟;刘慧;施德恒;孙金锋;朱遵略;吕淑霞;;一氟化碳电子态的光谱性质和预解离机理的理论研究[J];物理学报;2015年15期
4 刘晓军;苗凤娟;李瑞;张存华;李奇楠;闫冰;;GeO分子激发态的电子结构和跃迁性质的组态相互作用方法研究[J];物理学报;2015年12期
5 姚洪斌;郑雨军;;NaI分子的非绝热效应[J];物理学报;2011年12期
6 郑贤锋,余旭峰,崔执凤;C_2负离子B~2∑_μ~+←X~2∑_g~+激光诱导荧光激发谱[J];量子电子学报;2004年03期
,本文编号:1597754
本文链接:https://www.wllwen.com/shoufeilunwen/benkebiyelunwen/1597754.html