Spectroscopic Properties Of Low Electron States Of Fluorinated Diatomic Ions

The research and theoretical interpretation of molecular spectra has made great progress in recent decades,and the study of molecular spectra has become one of the most significant means of studying molecular structure.The potential energy functions of diatomic molecules and ions are very important research fields in atomic molecular physics which can describe the structure of the molecular electron fully.Diatomic molecular potential energy function relation with the nucleus spacing presents the function,so the molecular potential energy function is the basis of the atoms in the research of molecular physics,molecular spectroscopy study and molecular reaction dynamics and the foundation of the subjects,such as atomic molecular collision.Most importantly,the electronic spectrum introduced by the potential energy function has a vital theoretical and application value in the field of physics and other related disciplines.This article selects the BeF⁺ions as the research object,using the ab initio method research BeF⁺ion optical properties.In order to make the theoretical calculation of molecular spectroscopy data more accurate and obtain diatomic molecules and ions,the potential energy function method is particularly important.Here we adopt fully active space self-consistent field?CASSCF?optimization to calculation method for the back of the track,at the levels of consistent basis AV6Z aspirant inline contraction more reference configuration interaction?icMRCI?in icMRCI+Q/Q5+CV+DK calculated by the theoretical level of BeF⁺ion potential curve of 16 states.In order to get a more precise result,we have two kinds of correction for the potential curve which is calculated respectively for nuclear price correction and relativity correction,drawing the potential energy curve of the 16 states.Potential curve fits to get the spectrum constant?D_e,T_e,R_e,?_e,?_ex_e,?_ey_e,B_e,?_e and?_e?respectively,to calculate the vibration level of each vibration dynamic corresponding.In order to obtain more accurate results,the potential energy curve is combined with related theoretical correction,specifically,including Davidson correction,relativistic correction and nuclear price correction.Different algorithm has its own characteristics,for example for BeF⁺ions,free radicals,nuclear price correction is mainly is to use the cc-pCV5Z basis set to complete and implementation,and the relativistic correction is conducted on cc-pV5Z basis set level;For example,for O₂⁺ion,the modification of the nuclear price is made by using the cc-pCVQZ group,and the relativistic modification is calculated at the cc-pVQZ group level.The relativistic correction method adopted and applied in this paper is the second-order Douglas-Kroll Hamiltonian approximation.In addition,this article for the use of extrapolation formula is mainly related to extrapolation formula extrapolating to the total energy,and then the total energy extrapolation formula application to BeF⁺ions in various situations can curve extrapolation,at the same time and use the potential energy curve obtained by extrapolating the various calculations.However,the correlation electron spectrum results show that the total energy extrapolation formula given in this paper is reasonable and appropriate.