Theoretical Study Of The Dynamics For The Reaction C+CH

The ethanol radical C₂H is one of the most abundant polyatomic species in carbon-rich stars and interstellar clouds.C₂H is believed to be the major source of C₂ in comets and interstellar media.It is also the simplest organic triatomic molecule involving a triple C?C bond and has a low-lying electronic state.Moreover,C₂H plays an important role in the formation and the destruction of carbon chain molecules C₂Hn?with n=2-6?.The C₂H radical is not only the product of some reactions like C₂+ CH4,H2+ CH4 and the photo dissociation of acetylene,but also an important intermediate species of numerous combustion reactions.In order to investigate the details of the formation and destruction of C₂H,it is essential to study the relevant property of the molecular reaction dynamics.However,the experimental work concerning the dynamics of the title reaction is very sparse.To our knowledge,only three estimated values of the rate constant can be found in the literature and databases.So,In order to investigate the details of the formation and destruction of C₂H,it is essential to study the relevant property of the molecular reaction dynamics.Based on the 12A" global three-dimensional adiabatic potential energy surface,a theoretical study of the stereodynamics of the reaction C?3P?+CH?X2??has been performed using the quasi-classical trajectories?QCT?method.Our research includes collision energy,vibrational and rotational excitation and isotopic influences.Meanwhile,we concluded our caculation results and gave some reasonable explanations according to the characteristics of the PES and reaction mechanism.?1?we studied the effects of collision energy on this reaction.The reaction probabilities caculated by QCT are in good agreement with Boggio-Pasqua's.The reaction probabilities and cross sections are reduced with the increasing of the collision energy.The DCSs show that the higher collision energy,the lower forward-backward scatting of the title reaction.The product rotational angular momentum is oriented the y-axis and the direaction turn the negative to positive.?2?we studied the effect of reagent CH vibrational excitation on the dynamics properties of the title reaction.We calculated the CH for this reaction.The decreasing-then-increasing trend suggests that the intensity of this reaction firstly becomes weaker and then stronger as increasing the vibrational quantum number of CH.The DCSs show that the increase the vibrational quantum number of CH strengthen the trend of the forward-backward scatting of the title reaction.However,we found that the forward scatting achieves the maximum strength when the initial vibrational quantum number vCH=3.According to the study of random reaction trajectory,we found that the reaction time decreased with the increase of reagent vibrational number.Meanwhile,the reaction mechanism also changes which means the effect of the potential well decreases.The distributions of P??r?and P??r?show that the polarization degree of the product angular momentum is strengthened with the increase of reagent vibrational number.The product rotational alignment parameter<P2(j'·>which we calculated,confirms the correctness of the results.?3?we studied the effect of reagent CH rotational excitation on the dynamics properties of the title reaction.We calculated the CS for this reaction.The DCSs show that the increase the rotational quantum number of CH decrease the trend of the forward-backward scatting of the title reaction.The distributions of P??r?and P??r?show that the polarization degree of the product angular momentum decrease with the increase of reagent rotational states.?4?we studied the effect of reagent CH isotopic effect on the dynamics properties of the title reaction.We calculated the cross sections for different collision energy.We also studied the DCSs which indicated that the heavier particle are more likely to tend to be forward scatting.The distributions of P??r?and P??r?illustrates that the polarization degree of the product angular momentum decrease with the increase of reagent mass.We given some reasonable explanations of our dates and figures.Our study made the theoretical study of t the reaction C+CH more specific and perfect.