本文選題：CF~-負離子　切入點：CN自由基　出處：《太原科技大學》2017年碩士論文　論文類型：學位論文

【摘要】：碳元素是人類最早接觸和利用的元素之一,在自然界分布非常廣泛。碳化物分子包含許多重要的無機物分子(如CO_2、CH_4、CN等),并且是構成生命體的主要有機物分子,與我們的生活息息相關。而含碳雙原子分子作為最簡單的碳化物分子,更是受到了研究人員的廣泛關注。光譜是物質(zhì)的“指紋”,是對分子特性及內(nèi)部結構的最直接反應。因此,不論是通過理論計算光譜參數(shù)還是通過實驗光譜測量來研究分子的能級分布及光譜特性一直是學術界的熱門課題。本論文對含碳雙原子分子CF~-進行了量化計算,同時采用激光誘導擊穿光譜技術(LIBS)對CN自由基的振-轉(zhuǎn)躍遷譜線進行了測量。理論計算方面,我們采用MOLPRO量化計算軟件對CF~-負離子做了從頭計算。利用高精度的內(nèi)收縮多參考組態(tài)相互作用方法(icMRCI)基于相關一致基組aug-cc-pV5Z在0.8到7?的范圍內(nèi)計算了CF~-負離子兩個最低解離極限C(~3P_2)+F-(~1S_0)和C(~1D_2)+F-(~1S_0)對應的5個Λ-S態(tài)(X3Σ-,a1Δ,b1Σ+,A~3П和c1П)的勢能曲線。計算中考慮了標量相對論修正和Davidson修正使得計算結果更加可靠。根據(jù)?-S態(tài)的勢能曲線,求解徑向薛定諤方程得到了各電子態(tài)振轉(zhuǎn)能級,并擬合獲得了這些電子態(tài)的光譜常數(shù)(Te,Re,ωe,ωeχe,Be,αe,De)。此外,我們對CF~-負離子5個?-S態(tài)的電偶極矩曲線進行了計算,分析了電子態(tài)的組態(tài)變化對電偶極矩的影響。另外,我們計算了CF~-負離子A~3Π X3Σ-的躍遷偶極矩并采用LEVEL程序解得了Franck-Condon因子,分析了這兩個電子態(tài)之間的躍遷特性,獲得了A~3П的5個最低振動能級的輻射壽命τ,并給出了振子強度f00。最后,對CF~-負離子A~3П態(tài)的預解離機理進行了研究,并計算了A~3П態(tài)幾個高振動能級的解離壽命τd。實驗方面,我們采用LIBS測量了CN自由基B~2Σ~+ X~2Σ~+系統(tǒng)的振轉(zhuǎn)躍遷譜線。用Nd:YAG調(diào)Q脈沖激光器在空氣中對石墨樣品進行激光燒蝕,激光被聚焦到樣品靶點0.5mm以上位置,以期同時電離石墨樣品中的C原子及空氣中的N2分子形成高溫高能等離子體團。然后等離子體團中C原子跟N原子自由組合成CN自由基并自發(fā)輻射到低態(tài),我們再通過光譜儀對其輻射的熒光進行采集,得到了CN自由基B~2Σ~+ X~2Σ~+的振動躍遷譜線,并用LIFBASE軟件擬合出了X~2Σ~+的振動及轉(zhuǎn)動溫度,分別為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.
【學位授予單位】：太原科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O561.3

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