Theoretical Study On The Dielectronic Recombination Of High Charged Tungsten And Xenon Ions

The knowledge of accurate dielectronic recombination （DR） rates of heavy ions iscrucial for the study of ionization balance of highly ionized elements in hot plasmas. Theprocess therefore plays an important role in the theoretical modeling of plasmas, whetherin the laboratory or in astrophysical sources such as the solar corona. This knowledge isalso essential for the research of X-ray lasers especially for calculating the populating anddepopulating of lasing levels.Firstly, detailed calculations of DR rate coefficients and cross sections of W4³⁺ions byusing the Flexible Atomic Code （FAC） in the temperature region from1eV to50keV. Inthe low temperature, though the DR rate coefficients from the4p,3d and3p subshellexcitations are lower than the4s subshell excitation, the contribution can not be neglected.With the increasing of temperature, the contributions from3l shell excitations increase andits DR rate coefficients gradually overlap with that for4l shell excitations. For the3l shellexcitations, it can be noticed that the DR rate coefficient for3d subshell excitation is thelargest, the DR rate coefficient decreases with decreases of l quantum number. Thecontribution from Dn=2core excitation and n’>15can not be neglected at intermediateand high temperature. The obtained total DR rate coefficient is compared with the RR andTBR rate coefficients, and the results shown that DR rate coefficient is greater than othertwo recombination rate coefficients. Clearly, DR is predominate the ionization balance.Secondly, we also calculate the DR rate coefficients and cross sections of W4⁵⁺ions byusing the FAC. The results are presented for total DR rate coefficients and cross sectionsof the temperature from1to5×104eV. It shows that the contribution from4s subshellexcitation is the largest in the low energy region. DR rate coefficients from3p and3dsubshell excitations play an additional important role in the total DR rate coefficients athigh temperature. The largest contribution fromâ–³n=2core excitation is about30%atabove1000eV. For W4⁵⁺ions, the DR rate coefficients are also great than the RR ratecoefficients and TBR rate coefficients in the whole energy region.Finally, based on the fully relativistic configuration interaction method, theoreticalcalculations are carried out for the DR rate coefficients of Pd-like Xe⁸⁺ions. Thecomparison of the DR rate coefficients from4s,4p and4d subshell excitations shows that4d subshell excitation dominates in the whole temperature region, The contribution from 4p subshell excitation is very important and the DR rate coefficients of4d,4p subshellelectron excitation to4f subshell is the largest at temperature above10eV, thecontributions from4s subshell excitation is lower than7.5%in the whole temperatureregion. The contribution fromâ–³n=2core excitation can not be neglected, thecontributions from n’＞15can also not be neglected. The total DR rate coefficients aregreater than RR and TBR rate coefficients at temperature above1eV. Therefore, DR canstrongly influence the ionization balance of laser produced xenon plasmas.