林金全臺灣大學：化學研究所陳莉Chen, LiLiChen2007-11-262018-07-102007-11-262018-07-102005http://ntur.lib.ntu.edu.tw//handle/246246/51656經由激發-偵測技術搭配位能面計算(PES)，可以得到Ca(4s3d1D)+CH4 → CaH (X2Σ+)+CH3反應的初生態產物CaH之轉動振動光譜。藉由轉動振動光譜，可以進一步推測得知初生態CaH的轉動分佈，並可推得波茲曼轉動分佈溫度在振動態v=0及v=1時分別為1012±102K及834±70K。且可得知初生態CaH在不同的振動態v=0及v=1的分佈比例是CaH(v=0)/CaH(v=1)=3.97±0.26，其所對應到的波玆曼振動溫度為1313±173K。並可藉由轉動振動光譜推測得知產物初生態CaH之轉動及振動的能量分別是461±40cm-1及253.5cm-1。藉由壓力效應實驗，時間差效應實驗及能量效應實驗可以驗證反應產物CaH為初生態狀態，並非經由轉動冷卻或多次碰撞而得到的產物。在溫度效應實驗中，可以藉由阿瑞尼士方程式做佈居與溫度的倒數的關係圖，依據所得斜率可以求得此反應之反應能為2695±210cm-1，意即表示此反應進行為一吸熱反應。搭配位能面理論計算，可以進一步推知反應機制主要是採插入式。Ca(31D)以C2v或Cs對稱接近CH4。The reaction pathway for Ca(4s3d1D)+CH4→CaH(X2Σ+)+CH3 has been investigated by using the pump–probe technique in combination with potential energy surface (PES) calculations. The nascent product distributions of CaH have been found with a Boltzmann rotational temperature of 1012±102 K and 834± 70K for the v=0 and 1 levels, respectively, and summations of the (v’,v”)=(0,0) and (v’,v”)=(1,1) rovibrational intensities separately show that the population ratio of CaH(v=0)/CaH(v=1) yields a value of 3.97+0.26, which corresponding to a Boltzmann vibrational temperature of 1313±173 K. The rotational and vibrational energy partitions in CaH have been estimated to be 461±40cm-1and 253.5cm-1, respectively. The rotational distributions were obtained to be in the nascent states, free from interference of rotational cooling and secondary reaction processes by several dependences. The Arrhenius plot of the rotational intensity versus the reciprocal of temperature yields an activation energy, 2695+210cm-1, indicating that the reactive collision process should be an endothermic reaction. According to the PES calculations, the pathway is found to favor an insertion mechanism. Ca(31D) approaches CH4 in C2v or Cs symmetry.I. Introduction A. Preliminaries 1 B. Reaction dynamics of electronically excited alkaline earth atoms with RH (R=H, CH3,SiH3) molecules 2 1. Reaction dynamics of excited Mg atoms with RH(R=H, CH3, SiH3) molecules 2 2. Reaction dynamics of excited Ca atoms with RH(R=H, CH3, SiH3) molecules 6 C. Reaction dynamics of electronically excited alkali atom and hydrogen molecules 12 D. Reaction dynamics of electronically nonmetal atoms with methane molecules 18 1. Reaction dynamics of oxygen atoms with methane molecules 18 2. Reaction dynamics of nitrogen atoms with methane molecules 19 3. Reaction dynamics of fluorine atoms with methane molecules 21 4. Reaction dynamics of chlorine atoms with methane molecules 22 E. Fundamental spectroscopy theory involved in this experiment 23 1. Spectra of diatomic molecules 23 2. Hund’s case (a) 24 3. Hund’s case (b) 24 4. Rotation 25 5. Vibration 28 6. Selection rule for transition 29 7. Franck Condon Factor 30 8. Hönl-London factor 31 9. Thermal distribution of quantum states; Intensities in rotation-vibration Spectra 31 10. Laser-induced fluorescence(LIF) 33 11. 2Σ+-2Σ+ transition of CaH(B2Σ+- X2Σ+) 34 F. ab-initio methods 34 1. Hartree-Fock method 34 2. SCF technique 37 G. Methods to study the reaction mechanism 38 H. Reference 39 II. Experiment A. Preliminaries 44 B. Instruments 44 1. Heat-pipe apparatus 44 2. Laser system 47 3. Digital Oscilloscope 49 4. Control system 50 5. Detection System 51 6. Data acquisition program 53 C. Dye 54 1. LDS925 54 2. DCM 54 D. Experimental Procedure 54 E. Reference 56 III. Experimental Results and Discussions A. Preliminaries 57 B. Laser induced fluorescence spectrum 58 1. Spectrum of LIF 58 2. Data Processing 59 3. Rotation population distribution 67 4 Rotational temperature 68 5. Energy disposal 71 C. Dependences 73 1. Pressure dependence 74 2. Pump-probe delay time dependence 76 3. Energy dependence 77 4. Temperature dependence 79 5. Potential energy surface calculation 83 D. Comparison between the reactions of Ca(41P) and Ca(31D) with methane molecules 86 E. Reference 88 IV. Conclusions 908726371 bytesapplication/pdfen-US反應動力學鈣甲烷dynamicCathesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/51656/1/ntu-94-R92223047-1.pdf