Studies Of The Quantum Effects Of Hydrogen Atoms Moving On The Surface Of Pt Based On First-principles Calculations

In recent decades,surface and interface physics has become an increasingly im-portant sub-discipline in condensed matter physics.Its in-depth intersection between physics,crystallography,chemistry,biology and material science provides continuous impetus for the development of this field,including power semiconductor technology,molecular epitaxial growth,new materials and surface catalysis.Because the basic processes of surfaces play a key role in understanding heterogeneous catalysis,it is nec-essary to study surface processes at the atomic level.In particular,surface diffusion involves many important processes,including the growth and evaporation of crystals and films,chemical surface reactions,catalysis,etc.As the requirements for control-ling crystal growth on the atomic scale become higher,the actual importance becomes more and more significant.Hydrogen is the lightest element and is usually used as a test particle to establish basic concepts of surface science and evaluate surface reactions and related surface processes.Proton transfer plays a key role in the applications of advanced energy materials as well as in the functionalities of biological systems.In this work,based on the method of transfer matrix,we study the quantum effects of proton transfer in a series of one-dimensional(1D)model potentials and numerically calculate the quantum probability of transferring across single and double barriers(wells).In the case of single barriers,when the incident energies of protons are above the barrier height,the quantum oscil-lations in the transmission coefficients depend on the geometric shape of the barriers.It is found that atomic resonant tunneling(ART)not only presents in the rectangular double barriers as expected,but also exists in the other types of potential wells and dou-ble barriers.Furthermore,we have provided generalized analysis on the characteristics of transmission coefficients of hetero-structured rectangular double barriers.The quan-tum motions of hydrogen(H)atoms play an important role in the dynamical properties and functionalities of condensed-phase materials as well as biological systems.In this work,based on the transfer matrix method and first principles calculations,we study the dynamics of H atoms on a Pt(111)surface and numerically calculate the quantum prob-ability of H transferring across the surface potential fields.Atomic resonant tunneling is demonstrated along a number of diffusion pathways.Owing to resonant tunneling,an anomalous rate of transfer is predicted for H diffusion along a certain path at low temperatures.The role of nuclear quantum effects on the surface reactions involving H is investigated,by analyzing the probabilities of barrier crossing.The effective barrier is significantly reduced due to quantum tunneling,and it decreases monotonically with temperature within a certain region.For barrier-crossing processes where the van't Hoff-Arrhenius type of relation applies,we show the existence of a nonzero low-temperature limit of rate constant,which indicates nontrivial activities of H-involved reactions at cryogenic conditions.