Studies On The Dynamics Properties Of Several Reactions Of Alkaline Earth Metals And Halides

In this paper, several chemical reaction systems are studied with two theoretical methods.On one hand, the dynamics properties, such as the vibrational distribution, the reaction cross section and the product rotational alignment of the reactions Ca+CF3Br, Sr+CF3I, Ba+C6H5Br, Ba+m-C6H4BrCH3, Ba+C6H5C1and Ba+m-C6H4ClCH3are studied with the quasi-classical trajectory (QCT) method. For the reactions between alkaline earth metal atom and halogenated alkane, take the reactions Ca+CF3Br and Sr+CF3l as examples, their vibrational distributions increase at first and then decrease with the increasing of the vibration quantum numbers, with their changing shapes similar to the bell-shape. The fact that the value of reaction cross section of the reaction Ca+CF3Br decreases with the increasing collision energy is due to a potential well existing on its London-Eyring-Polanyi-Sato (LEPS) potential energy surfaces (PES). For the reaction Sr+CF3l, because of a reaction barrier on its LEPS PES, the reaction cross section increases with the increasing collision energy. While both product rotational alignments of the two reactions decrease with the increasing collision energy. As for the reactions of alkaline earth metal atom with benzene halide and benzyl halide, such as the reactions Ba+CeHsBr, Ba+m-C6H4BrCH3, Ba+C6H5Cl and Ba+m-C6H4ClCH3, their vibrational distributions all decrease with the increasing of the vibration quantum numbers. The above results also show that their reaction cross sections all gradually increase with the increasing of the collision energies. The product rotational alignments of the reactions Ba+C6H5Br and Ba+m-C6H4BrCH3at first increase and then decrease with the increasing of the collision energies, while the product rotational alignment of the reaction Ba+C6H5Cl decreases with the increasing of the collision energy and that of the reaction Ba+m-C6H4ClCH3decreases at first and then increases with the increasing of the collision energy. Vibrational distributions of the six above mentioned reactions obtained are consistent with their corresponding experimental results, respectively. The reaction mechanisms of the six reactions are analysed, some conclusions are obtained and the differences between the theoretical and experimental results are explained.On the other hand, the rate constants of the two unimolecular reactions in the reaction system CH3OCH2+O2→CH3OCH2OO...TS1→H2OCH2OOH...TS2→CH +2CH2O are calculated with the Gaussian03program, RRKM theory and Yao-Lin (YL) method. The anharmonic effects of these two unimolecular reactions are found to be more and more significant with the increasing of the temperature and energy. It is concluded that the anharmonic effects are not negligible in the two unimolecular reactions.