Relativistic Study On The Energy Level Structure And Radiative Transition Properties Of Oxygen Atom

Based on the multi-configuration Dirac-Hartree-Fock method,the line strength,transition probability and branching ratio of neutral oxygen atom metastable 2p³3s⁵S₂ are accurately calculated.Core-core,core-valance and valance-valance correlation effects,Breit interaction and QED effect were considered.The uncertainty of evaluating the residual electron correlation effect is given.The results show that the core correlation effect has a certain influence on the accurate calculation of the level splitting of ³S and ⁵S in the p³s configuration.It is found that the branching ratio of ⁵S₂ is stable in different correlation model calculations.We infer that this is a special inherent property that is of great value for plasma diagnosis and other applications.Due to the Breit interaction,the transition probability of ⁵S₂ changed considerably.Because ³P₂-⁵S₂(135.560nm)and ³P₁-⁵S₂(135.851nm)have different sensitivities to this effect.This also affects the calculation of branch ratios and lifetimes.In addition,through the analysis of different calculation results for different multi-reference configurations,it is found that the 5S2 transition matrix element is more sensitive to the electron correlation effect in the calculation of length specification than in the velocity specification.This may also lead to some errors in calculating the lifetime of ⁵S₂ in the length specification.At the same time,we use the collision radiation model to calculate the collision excitation intensity and transition probability of oxygen atom in the ground state.The temperature of lightning channel is estimated according to the intensity ratio of oxygen atom correlation spectral line,which is consistent with the results of the multi-line method.It shows that it is feasible to use the collision radiation model to diagnose lightning temperature.