Dynamics Study Of The Reaction H+HS And H+CH

The H+HS reaction studied in this paper as one of the most simple molecularreactions plays a very important role in theoretical research and real life. We use in ourlife, for example, the chemical fuels such as coal and oil, sulfur elements are widelyexisted. Moreover, In the combustion and atmospheric chemistry, sulfur atom or sulfideinvolved in chemical reactions also has a very important application. So, the chemicalreactions of containing sulfur elements play a very important role in daily life, airpollution, environmental protection and governance.The main work in this paper is based on the latest build potential energy surface ofthe H+HS system, used the quasi-classical trajectory(QCT)method to study the dynamicproperties of the H+HS chemical reaction. The potential energy surface of the H2S systemwe studied in this paper is very characteristic: the potential energy surface exist tworeaction channels, respectively is abstraction and exchange reaction. Therefore, it canprovide abundant information of the dynamic properties research. In2012, LvShuangjiang et al. used the CASSCF method and the MRCI method based on CASSCFto build a new and high accuracy potential energy surface of the H2S, at the same time,they present an exact quantum dynamical study and quasi-classical trajectory (QCT)calculations for the abstraction and exchange processes for the tlttle reaction. And atthe total momentum J=0, a good agreement isfound between the QCT and TDWPreaction probabilities. Based on this latest initio potential energy surface (PES) build byLv et al.. We studied the dynamics properties of the reaction H+HS and compared theresults with Lv et al.. In addition,We also studied the vibrational and rotationalexcitation impact for the two reaction channels. The results of the rotational excitationeffect on the reaction shows that, when the collision energy is higher than0.32eV,rotational excitation response to the abstraction and exchange reaction have littleimpact. When the collision energy is lower than0.32eV, for the abstraction reaction,with the increasingof the rotational state（v=0, j=0,1,2,3）the reaction cross sectionis also increase. Due to the barrier height is0.31eV, so there is no reaction to take placewhen the collision energy is lower than0.31eV. The results of the vibrational excitationeffect on the reaction shows that, vibrational excitation of the reactant can promote theabstraction and exchange reactions. We can obtain the following conclusion: the abstra- ction reaction is the dominant process at low collision energy, while the exchangeprocess becomes dominant quickly over the abstraction channels when the collisionenergy exceeds the barrier height of the exchange reaction, that is owing to that theexchange reaction has a larger acceptance cone than the abstraction reaction.Stereodynamics which is focusing on the research of the correlations of angularmomentum and other vectors in the processes of chemical reaction has developed andmade a great achievement in both theoretical and experimental aspects. In this paper,we not only studied the reaction dynamics properties, but also studed thestereodynamics properties of the title reaction used the quasi-classical trajectory(QCT)method. The results shows that: for the abstraction reaction, the productrotational angular momentum vector j’ is distributed with cylindrical symmetry in theproduct scattering frame, and the product rotational angular momentum vector j’ is notonly strongly aligned, but also oriented along the negative y-axis. The higher thecollision energy is，the weaker the polarized behavior is. For the exchange reaction, thehigher the collision energy is, the strong the polarized behavior is. Vibrational androtational excitation on the results of the studies indicate that: at higher collisionenergies, rotational excitation is almost no effect on the two reaction channels. At lowercollision energies, with the increasing of the rotational excitation, the weaker of therotational alignment effect for the the product and the product rotational angularmomentum vector j’ is not only strongly aligned, but also oriented along the negativey-axis. In all collision energies, the greater the value of vibrational excitation v, theweaker the degree of the product orientation. And the reactions mainly show theforward or backward scattering. In a word, the initial collision energy, vibrational androtational excitation have a strong impact for the rotation polarization effect of theproduct.In addition, we briefly described the reaction H+CHâ†'H2+C(1D).We studied theinfluences of different vibrational state(v=0-3) for the polarization of the product H2.The results shows that the deep well on the potential energy surface and the differentvibrational state have important influence on product molecules.