Radiative Parameters And Hyperfine Structure Of Excited States Of Ir Ⅱ,V Ⅰ And V Ⅱ

In recent decades,with the rapid development of laser technology,plasma technology and photoelectric detection technology,the measurement technologies of atomic radiative parameters（radiative lifetime,branching fraction,transition probability and oscillator strength）,hyperfine structure（HFS）and isotope shift（IS）were constantly improved.These data have important applications in astrophysics,atomic physics,plasma physics,fusion physics and other fields.In astrophysics,accurate atomic data are applied to the analysis of high-quality astronomical spectra to diagnose plasma in stars,determine stellar elemental abundances,calculate atmospheric radiative transfer,and simulate stellar atmosphere.In atomic physics,reliable experimental atomic data can help to optimize atomic theory calculation models and play a crucial role in testing and improving the accuracy of atomic theory calculations.Considering the important values of vanadium and iridium in astronomical spectral analysand atomic theory calculations,as well as their important effects in the alloys of fusion blanket structural materials,the radiative parameters and HFS constants of the high excited states in Ir Ⅱ,V Ⅰ and V Ⅱ were investigated in this work.In this paper,the radiative lifetimes were combined with the branching fractions to determine the transition probabilities and oscillator strengths.The radiative lifetimes of Ir Ⅱ and V Ⅱ levels were measured by time-resolved laser-induced fluorescence（TR-LIF）technique,and the radiative lifetimes of Ir Ⅱ levels were also obtained by the pseudo-relativistic Hartree-Fock method including core-polarization contributions（HFR+CPOL）.The experimental lifetimes were combined with the branching fractions calculated by the HFR+CPOL method to determine the semi-empirical transition probabilities and oscillator strengths of the spectral lines of Ir Ⅱ.By combining the experimental lifetimes with the experimental branching fractions measured by Fourier transform spectra from the National Solar Observatory（NSO）database,the transition probabilities and oscillator strengths of the spectral lines of V Ⅰ and V Ⅱ were determined.The HFS constants of V Ⅰ and V Ⅱ were investigated by analyzing the spectral lines of Fourier transform spectra from NSO database with a fitting program written by combining HFS theory and the Levenberg-Marquardt（LM）least squares method.The main research results in this work are as follows:1.The radiative lifetimes of 15 odd-parity levels from 47003 to 61474 cm^-1 of Ir Ⅱ were measured by TR-LIF technique.The lifetimes and branching fractions of these levels were calculated by HFR+CPOL method in collaboration with the Quinet research group of Mons University,Belgium.The semi-empirical transition probabilities and oscillator strengths of 124 spectral lines in the wavelength range between 194 and 361 nm were determined by combining experimental lifetimes with theoretical branching fractions.11lifetimes among these levels were reported for the first time,and the uncertainties of most of the results were less than 10%except for one level that has an uncertainty of 16%.For the lifetimes of four levels reported in the literatures,our measurements are in good agreement with the literature results.The results we obtained largely complement the data on the radiative parameters of the Ir Ⅱ levels.2.The radiative lifetimes of 27 odd-parity levels from 34592 to 62285 cm^-1 of V Ⅱ were measured by TR-LIF technique.The lifetime values of 23 of these energy levels are reported for the first time,and the uncertainties of all the results are within 10%.For the remaining four energy levels with previous results,the measurements in this work are in good agreement with the previous results,and the deviations of most of the results are within10%.The branching fractions of the corresponding transitions were measured by the intensities of spectral lines of the Fourier transform spectra for the vanadium hollow cathode lamp for the NSO database.The transition probabilities and oscillator strengths of 103 lines in the wavelength range between 252 and 565 nm were determined by combining the experimental lifetimes with branching fractions.3.Using the HFS theory and the least-squares fitting method called LM,we wrote a parameter fitting program to fit the profiles of spectral lines from Fourier transform spectra to determine the HFS constants.The magnetic dipole HFS constant A values for 53 levels of V Ⅰ between 28313 and 52948 cm^-1 and for 56 levels of V Ⅱ between 36 and 72952 cm^-1are obtained,of which 46 results for V Ⅰ and 50 results for V Ⅱ are reported for the first time,as far as we know.For the seven levels of V Ⅰ and the six levels of V Ⅱ for which previous results are available,the A values of these levels determined in this work are consistent with the previous results.