Spectroscopic Properties Investigations Of Diatomic Molecule PN And Ionic PS~+

Molecular spectroscopy is an effective means to study the internal structure and properties of molecules,which plays a important role in the atomic and molecular physics.By the understanding of the molecular spectroscopy,we can obtain the molecular vibraitonal energy levels,rotational energy levels,et al.Molecular spectra can also be used to detect and identify the components of various molecules,ions and radicals in stars,planets,comets and interstellar space,providing important reference information for astrophysics.Phosphorus plays an important role in biochemistry and astrophysics,being expected to be one of the candidates in star and meteorite evolution to provide the necessary life building material.To date,only phosphorus mononitride,as the first phosphorus-bearing species,has been identified in interstellar medium and atmospheres.Hence,spectral information of gas phase PN has attracted intense research interest over the past several decades.The thiophosphorus radical and its ion have been investigated by spectroscopic methods since 60 years ago.From then on,the P-bearing molecules appear to have been the object of a few experimental and theoretical studies.However,to our surprise,most studies focus on the neutral PS molecule.Experimental observations for the ionized forms of PS were scarce,and the transition data of PS⁺are relatively limited.Through the study of PN molecules and PS⁺ions,this paper is able to clearly obtain their various physico-chemical properties,accurately predict their spectral and transition properties,and provide theoretical data support for interstellar observations and laboratory studies.In this paper,the potential energy curve of 103Ωstates generated from the 39Λ-S states of PN have been calculated using the internally contracted multireference configuration interaction method with the Davidson modification.Core-valence correlation and scalar relativistic corrections,as well as the basis-set extrapolation to the complete basis set limit are considered.The spin–orbit coupling is computed using the state interaction approach with the Breit-Pauli Hamiltonian.The spectroscopic parameters and molecular constants of bound and quasiboundΛ-S andΩstates are evaluated.This paper calculated spectroscopic results agree quite well with the available experimental data.The interactions among different electronic states in curve crossing regions have been discussed with the help of computed spin?orbit coupling matrix elements.The perturbations and predissociation phenomena of the A¹П,b³П,D¹Δ,E¹Σ⁺,and 2¹Пstates and so on have been revealed.Ab initio calculations have been performed to study the transition properties of the PS⁺cation.Transition dipole moments of fourteen dipole-allowed transitions,between the X¹Σ⁺,A¹Σ^-,B¹Δ,C¹Π,D¹Σ⁺,E¹Π,and F¹Σ⁺states,have been calculated with the aug-cc-p V6Z basis set.Transition probabilities,band origins,as well as radiative lifetimes of vibronic emissions are predicted.The vibrational radiative lifetimes are estimated to be in order of 10^-8s for the D¹Σ⁺,F¹Σ⁺,and first well of E¹Πstates;10^-7s for the C¹Πstate;10^-3-10^-4s for the second well of E¹Πstate.Various curve crossings and avoided crossings are revealed with the help of our computed spin-orbit coupling matrix elements.The intricate couplings among different electronic states are analyzed investigated.This paper propose that the curve crossing with the D¹Σ⁺state may be responsible for the fact that the C¹Πν’≥14 vibrational levels cannot be detected in experiment.