High-precision Structural Ab Initio Study Of HF Divalent Cations

The studies of atomic and molecular structure and kinetic properties have been of long-standing interest due to their widespread existence in astrophysics,plasma physics,interstellar chemistry and planetary ionosphere.Unlike the highly charged or neutral systems,both Coulomb repulsive and chemical attractive interaction play important roles in dications,and their nonadiabatic interactions lead to complex avoided crossings,and the possibility of forming a metastable state.These metastable states of dications are of particular interest for both experiments and theories as they can be observed in absorption and emission spectroscopy,fragmentations,ion scatterings,Auger process and so on.The related properties have attracted the attention of experimental and theoretical workers in recent years.Highly-precision electronic structure parameters,such as potential energy curves,are urgently needed in related studies.However,the study of electronic structure of dications is still very challenging due to the presence of repulsive-bond to avoided crossings.In this work,we focus on the study of typical small molecule divalent cations HF2+,not only because of their importance in many fields,but also on the systematic study of metastable structures around their avoided crossings.In the structure of the paper,first of all,we outline the research status of the subject background and related theoretical experiments,and briefly describe the basic theoretical knowledge and related techniques involved in the ab initio study.The important influence of dynamic electronic association on non-adiabatic coupling systems is discussed.After that,we select the typical dication HF2+ as the research object by using Molpro 2012 quantum chemical package,and use the multi-reference configuration interaction method to calculate it,and give 36 electron state adiabatic potential energy curves containing 12 repulsive branches and 3 attractive branch dissociation limits;for attractive branch potential energy curves,we give the bound state spectral constant,the transition dipole moments,the permanent dipole moments and the radial coupling matrix and other structural parameters;Finally,using the quantum scattering method and the WKB method,the resonance parameters of the repulsive-bounded pre-dissociation states are given.At present,the research work on HF2+ is very limited,our research results are in good agreement with the existing theories and experiments.at the same time,our theoretical calculations have higher accuracy and give many important physical parameters for the first time,which proves the reliability of our treatment methods for such systems.Relevant experience can be extended to other dications systems in the future.