Experimental Study Of Ion-Molecule Charge-Exchange Reaction Between Low-Energy Ar~+ And CO

Ion-molecule collision reaction is an important chemical reaction process.Among them,the study of gas-phase reaction kinetics reveals many chemical reaction kinetic processes,which plays an important role in promoting the development of reaction kinetics.Since the mid-1950s,the reaction of ions and molecules has become one of the main research topics in the field of chemistry and physics today.Because ions are charged,they are easier to manipulate and detect than molecules.In addition,the collision cross-section of ions and molecules is usually much larger than the collision cross-section of two neutral particles of similar mass,and the reaction can be studied even when the concentration of the reactants is very rare.For chemical reactions,ion-molecular reactions in the low collision energy range(below 20 electron Volts)are more important.Our experimental group developed a low-energy ion-molecule reaction velocity imaging device and used it to study the dynamics of collision reaction between gas-phase molecules/atoms and ions.The reaction process involves the essential characteristics of chemical reactions,such as charge transfer,energy transfer,and chemical processes such as breaking and recombination of molecular bonds.By measuring the momentum distribution in the three-dimensional space of product ions,dynamic information at the quantum state level can be obtained,thereby revealing the nature of the charge transfer process.Our experimental group combined ion velocity slice imaging technology and ion-molecule cross-beam method to build a self-developed low-energy ion-molecule reaction device,we used this device to carry out the study of the charge exchange(transfer)reaction of Ar+CO→Ar+CO+at the center-of-mass collision energies of 4.40,6.40,and 8.39 eV.A detailed analysis of the time slice velocity image of the products CO+are obtained by the experiment,and we found that the population of CO+at A2Π state is predoiinant in the present collision energy range,and the forward-scattered CO+yields show the broader angular distribution at the higher collision energy in the reaction.Combined with our summary of existing charge transfer reactions,it is found that within this collision energy range,the intimate collision mechanism of intermediates that may experience(Ar-CO)+still plays an important role.Previous studies have suggested that under such a high collision energy,the collision reaction cannot experience such an intermediate.This work is one of our series of studies on ion-molecular charge transfer mechanisms and plays an important role in understanding various charge transfer collision process mechanisms.For this reason,we provide another experimental evidence for the charge transfer process mechanisms.