Theoretical Studies On Energy Dissipation Dynamics Of H₂O And CO On Metal Surfaces Based On Neural Network Potential Energy Surfaces

Conversion of energy at the gas-surface lies at the heart of many industrial applications.Dissipation of parts of this energy into the substrate bulk drives the thermalization of surface,but also constitutes a potentially unwanted loss channel.The study of energy dissipation during energy exchange is of great significance for the regulation of gas-surface dynamics.Considering the complexity of this system,the current quantum dynamic calculations cannot consider the degrees of freedom of surface and thus cannot describe the energy dissipation process.As an effective tool to explore quantum resolved dynamics,quasi-classical trajectory(QCT)method has been widely used in various gas-surface interaction systems.Ab initio molecular dynamics method based on first principles can achieve accurate simulation of direct dynamic processes(such as direct scattering and dissociation).However,considering the computational cost,this method cannot efficiently simulate the interactions with long times(such as adsorption,trapping)or rare events(such as state-to-state scattering).The Embedded atom neural network potential energy surface(EANN PES)based on first principle data fitting provides a good solution:it can carry out a large number of theoretical simulation with long propagation time under the premise of ensuring the accuracy.In this dissertation,the dynamics of H2O+Pt(110)-(1 × 2)and CO+Au(111)are simulated by means of EANN PES and QCT method,and the energy dissipation process is systematically studied.The interfacial properties of H2O on metal surfaces are of great technical importance.Experimentally,it is observed that the initial sticking probability(S0)of H2O on Pt(110)-(1 × 2)exhibits activation adsorption characteristics with the change of incident energy.In order to explain the experimental phenonmenon,the So of H2O on Pt(110)-(1 × 2)under different incident energies are calculated and compared with the experimental results.It is found that the non-adiabatic energy dissipation and the rotational alignment are not the main cause of the experiment.Results of theoretical calculations provide direct microscopic insights for understanding the energy dissipation process of H2O sticking on Pt(110)-(1 × 2),and provide valuable reference information for furture research.The long residence lifetime of CO on Au(111)has attracted extensive attention,especially recent experiments and theories have revealed the complex interaction between the weak physisorption and chemisorption of CO on Au(111).However,the effect of unit cell size on dynamic results is often ignored in theoretical simulations.In this dissertation,the adiabatic energy dissipation dynamics of CO(vi=2)on Au(111)with different unit cell size are explored by virtue of the good scalability of EANN PES.The results show that the unit cell size has no significant effect on the scattered CO,increasing the unit cell size alleviates the unphysical heating of surface and increases the trapping probability of CO.These results further deepen the understanding of the adiabatic energy dissipation dynamic process of CO+Au(111)system,and lay a foundation for the accurate and efficient dynamic theoretical research of large-scale cell with the help of EANN PES.The vibrational relaxation of high vibrational excited CO on Au(111)is another widely studied topic of CO+Au(111)system.The weak vibrational relaxation of CO(vi=17)on Au(111)is in sharp contrast to the multi-quantum vibrational relaxation of NO(vi=16)on Au(111).Exploring the vibrational energy transfer process is of great significance to understand the vibrational relaxation law of gas molecules on the surface.The vibrational relaxation of CO(vi=17)on Au(111)is calculated and compared with NO+Au(111)system.The results show that under the framework of electron adiabatic dynamics,the theoretical calculation reproduces the objective law that the vibrational relaxation of CO is weaker than that of NO,and show stronger vibrational inelasticity than that of experiment,indicating that the nonadiabatic effect can not be confirmed by experiment alone as the main mechanism of vibrational relaxation of CO on Au(111).In addition,it it found that the morphology of the adiabatic potential energy surface in the transition state region is very important for the vibrational relaxation process.The calculation results of this dissertation confirm the mechanism of vibrational relaxation of CO on Au(111)and the cognition of vibrational relaxation of gas molecules on surface has been pushed to a new height.