Exploring the dynamics of reaction N(2D)+C3H6 with crossed-molecular-beam experiments and quantum-chemical calculations

• Main Authors: Hsieh, Chu-Chun, 謝筑鈞
• Other Authors: Lee, Shih-Huang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/97108718818347352718

碩士 === 國立交通大學 === 應用化學研究所 === 98 === The reaction of N (2D) + C3H6 was investigated by crossed molecular beam technique and quantum-chemical calculations. Nitrogen atom was generated by a high-voltage discharge device. The collision energy is about 5.3 kcal mol-1. The products are ionized by a tunable VUV radiation then selected by a quadrupole mass filter. Finally we obtained the time-of-flight spectra of products. After simulating the time-of-flight spectra, we obtained the distribution of translational energy and the distribution of angular distribution under center of mass frame. In order to realize the dynamics of this reaction, we calculated the potential energy surface (PES) of this reaction by quantum-chemical calculations of density functional theory and coupled cluster. There are three product channels: C3H5N + H, C3H4N + 2H and C2H3N + CH3. Using the maximum translational energy of translational energy distribution and PES, we suggested that the structure of products are H2CHNCH2 + H, CH3CHCN + 2H and c-CH2(N)CH + CH3, respectively . The reaction pathway is mainly through the addition of N(2D) to πbond on the C3H6, then form a cyclic intermediate. The cyclic intermediate forms the products directly or after isomerization then forms the products. Compared with the past result of reaction N (2D) + C2H4, only one product channel C2H3N + H is observed. The angular distribution of C2H3N is partial to forward. But compared with the similar product channel C3H5N+H of reaction N (2D) + C3H6, the angular distribution of C3H5N is partial to backward. The different shows that the pathways of these two reactions to generate a hydrogen atom are not the same. The angular distribution of CH3CHCN is isotropic. It implies that the formation of CH3CHCN is through multiple isomerizations. The experimental results of reaction N (2D) + C2H4 didn’t report the formation of C2H2N + 2H. The angular distribution of c-CH2(N)CH is partial to forward. It implies that the formation of c-CH2(N)CH is through a short-lived complex. Using crossed molecular beam technique and PES of quantum-chemical calculations, we demonstrated the informations of reaction N (2D) + C3H6. And the results testify again that this technique is a powerful tool for research of chemical reaction dynamics.