We have investigated the dynamics of the F＋C4H6 reaction using the universal crossed molecular beam method. The C4H5F＋H reaction channel was observed in this experiment. Angular resolved time-of-flight spectra have ...We have investigated the dynamics of the F＋C4H6 reaction using the universal crossed molecular beam method. The C4H5F＋H reaction channel was observed in this experiment. Angular resolved time-of-flight spectra have been measured for the C4H5F product. Prod- uct angular distributions as well as kinetic energy distributions were determined for this product channel. Experimental results show that the C4H5F product is largely backward scattered with considerable forward scattering signal, relative to the F atom beam direction. This suggests that the reaction channel mainly proceeds via a long-lived complex formation mechanism, with possible contribution from a direct SN2 type mechanism.展开更多
Ab initio electronic structure calculations at 6-31G** level were performed to determine the mechanism of the isomerization reaction from 1, 2-butadiene to 1, 3-butadiene. The MP2 method was used to improve the barrie...Ab initio electronic structure calculations at 6-31G** level were performed to determine the mechanism of the isomerization reaction from 1, 2-butadiene to 1, 3-butadiene. The MP2 method was used to improve the barrier energies of the reaction. The calculation results show that the reaction is a stepwise process via a radical INT; the barrier energies determined forTS1 and TS2 at UMP2/6-31G**//UHF/6-31G**+ZPE level are 64.95×4.184 and 64.10×4.184 kJ/mol, respectively. Based on the unified statistical theory, the thermal rate constants for the present complex reaction mechanism were computed over the termperature range 1100–1600 K. The computed thermal rate constants for the reaction are well represented by the following Arrhenius expression:k(T) = 2.4×1013 exp (- 62.8 kJ/RT) s-l. The theoretical investigations are found to be in quantitative agreement with the experimental results.展开更多
文摘We have investigated the dynamics of the F＋C4H6 reaction using the universal crossed molecular beam method. The C4H5F＋H reaction channel was observed in this experiment. Angular resolved time-of-flight spectra have been measured for the C4H5F product. Prod- uct angular distributions as well as kinetic energy distributions were determined for this product channel. Experimental results show that the C4H5F product is largely backward scattered with considerable forward scattering signal, relative to the F atom beam direction. This suggests that the reaction channel mainly proceeds via a long-lived complex formation mechanism, with possible contribution from a direct SN2 type mechanism.
文摘Ab initio electronic structure calculations at 6-31G** level were performed to determine the mechanism of the isomerization reaction from 1, 2-butadiene to 1, 3-butadiene. The MP2 method was used to improve the barrier energies of the reaction. The calculation results show that the reaction is a stepwise process via a radical INT; the barrier energies determined forTS1 and TS2 at UMP2/6-31G**//UHF/6-31G**+ZPE level are 64.95×4.184 and 64.10×4.184 kJ/mol, respectively. Based on the unified statistical theory, the thermal rate constants for the present complex reaction mechanism were computed over the termperature range 1100–1600 K. The computed thermal rate constants for the reaction are well represented by the following Arrhenius expression:k(T) = 2.4×1013 exp (- 62.8 kJ/RT) s-l. The theoretical investigations are found to be in quantitative agreement with the experimental results.
