林志民Lee, Yuan-Tseh;Lin, Jim J.臺灣大學:化學研究所方靜雯Fang, Jing-WenJing-WenFang2010-06-302018-07-102010-06-302018-07-102008U0001-2207200810442100http://ntur.lib.ntu.edu.tw//handle/246246/187434The reaction of F2 + C3H6 was investigated using crossed molecular beam technique for a wide range of collision energy. The F + C3H6F was observed to be the only primary product channel; the HF + C3H5F product channel was searched but not found. The relative reaction cross section was measured as a function of collision energy; the reaction threshold was determined to be 2.4 ? 0.3 kcal/mol. Time-of-flight spectra and angular distributions of the products were measured and analyzed. The center-of-mass frame angular distribution displayed strongly backward, indicating that the reaction time scale is much shorter than one rotational period of the collision complex. All experimental results support a rebound reaction mechanism, which agrees with the structure of the calculated transition state. The transition state geometry suggests an early barrier; such dynamics is consistent with the small kinetic energy release of the products observed in the experiment. Compared with the F2 + C2H4 reaction, both the experimental and computational results in the present reaction give the same trend that the methyl-substitution effect in propene reduced the reaction threshold by about 3 kcal/mol.Acknowledgments…vhinese Abstract…vibstract…viiigure Captions…xhapter 1 Introduction…1hapter 2 Experimental Section…10.1 Investigation reaction dynamics using crossed molecular beam technique…10.1.1 Finding the optimized crossing time…12.1.2 Measurement of the molecular beam velocity…13.1.3 Measurement of angular divergence of molecular beam…15.2 Apparatus details…15.2.1 Source chamber…16.2.2 Main chamber…17.2.3 Detector…18.3 Data section…19.3.1 Newton diagram…19.3.2 Laboratory (LAB) to center-of-mass (CM) transformation…21.3.3 Physical interpretation of CM-frame angular distribution…23.3.4 Hard sphere model…25hapter 3 Results…28.1 Identification of product channels…28.1.1 Search for product channel (R1)…28.1.2 Identification of product channel (R2)…29.1.3 Search for product channel (R3)…31.1.4 Search for product channel (R4)…33.2 Dynamics of product channel (R2)…34.2.1 LAB-frame TOF spectra and CM-frame angular distributions…34.2.2 Excitation function…39hapter 4 Discussion…43hapter 5 Summary…51eferences…53ppendix I Experimental conditions for different collision energies…55ppendix II Ab initio calculations for F2 + C3H6 reaction y Dr. Tingxian Xie…57ppendix III "Dynamics of the F2 reaction with the simplest -bonding molecule", Y.-J. Lu, T. Xie, J.-W. Fang, H.-C. Shao and J. J. Lin, J. Chem. Phys. 128, 184302 (2008)…592027738 bytesapplication/pdfen-UScrossed molecular beamdynamicsbackward scatteringearly barriermethyl-substitution effectthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/187434/1/ntu-97-R95223014-1.pdf