CF~-、CN分子的光譜特性研究
本文選題:CF~-負(fù)離子 切入點(diǎn):CN自由基 出處:《太原科技大學(xué)》2017年碩士論文 論文類(lèi)型:學(xué)位論文
【摘要】:碳元素是人類(lèi)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(wú)機(jī)物分子(如CO_2、CH_4、CN等),并且是構(gòu)成生命體的主要有機(jī)物分子,與我們的生活息息相關(guān)。而含碳雙原子分子作為最簡(jiǎn)單的碳化物分子,更是受到了研究人員的廣泛關(guān)注。光譜是物質(zhì)的“指紋”,是對(duì)分子特性及內(nèi)部結(jié)構(gòu)的最直接反應(yīng)。因此,不論是通過(guò)理論計(jì)算光譜參數(shù)還是通過(guò)實(shí)驗(yàn)光譜測(cè)量來(lái)研究分子的能級(jí)分布及光譜特性一直是學(xué)術(shù)界的熱門(mén)課題。本論文對(duì)含碳雙原子分子CF~-進(jìn)行了量化計(jì)算,同時(shí)采用激光誘導(dǎo)擊穿光譜技術(shù)(LIBS)對(duì)CN自由基的振-轉(zhuǎn)躍遷譜線進(jìn)行了測(cè)量。理論計(jì)算方面,我們采用MOLPRO量化計(jì)算軟件對(duì)CF~-負(fù)離子做了從頭計(jì)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(guān)一致基組aug-cc-pV5Z在0.8到7?的范圍內(nèi)計(jì)算了CF~-負(fù)離子兩個(gè)最低解離極限C(~3P_2)+F-(~1S_0)和C(~1D_2)+F-(~1S_0)對(duì)應(yīng)的5個(gè)Λ-S態(tài)(X3Σ-,a1Δ,b1Σ+,A~3П和c1П)的勢(shì)能曲線。計(jì)算中考慮了標(biāo)量相對(duì)論修正和Davidson修正使得計(jì)算結(jié)果更加可靠。根據(jù)?-S態(tài)的勢(shì)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(jí),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(duì)CF~-負(fù)離子5個(gè)?-S態(tài)的電偶極矩曲線進(jìn)行了計(jì)算,分析了電子態(tài)的組態(tài)變化對(duì)電偶極矩的影響。另外,我們計(jì)算了CF~-負(fù)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(gè)電子態(tài)之間的躍遷特性,獲得了A~3П的5個(gè)最低振動(dòng)能級(jí)的輻射壽命τ,并給出了振子強(qiáng)度f(wàn)00。最后,對(duì)CF~-負(fù)離子A~3П態(tài)的預(yù)解離機(jī)理進(jìn)行了研究,并計(jì)算了A~3П態(tài)幾個(gè)高振動(dòng)能級(jí)的解離壽命τd。實(shí)驗(yàn)方面,我們采用LIBS測(cè)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(duì)石墨樣品進(jìn)行激光燒蝕,激光被聚焦到樣品靶點(diǎn)0.5mm以上位置,以期同時(shí)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(tuán)。然后等離子體團(tuán)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?cè)偻ㄟ^(guò)光譜儀對(duì)其輻射的熒光進(jìn)行采集,得到了CN自由基B~2Σ~+ X~2Σ~+的振動(dòng)躍遷譜線,并用LIFBASE軟件擬合出了X~2Σ~+的振動(dòng)及轉(zhuǎn)動(dòng)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(xué)位授予單位】:太原科技大學(xué)
【學(xué)位級(jí)別】:碩士
【學(xué)位授予年份】:2017
【分類(lèi)號(hào)】:O561.3
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