Xe^(8+)离子双电子复合速率系数的理论研究

Dielectronic Recombination of Xe^(8+) Ions

利用基于全相对论组态相互作用理论的FAC程序包,详细研究了温度在0.1～1650 eV范围内Xe8+离子的双电子复合(DR)过程。通过比较4s,4p和4d壳层电子激发的双电子复合速率系数,发现温度在10 eV以上时,内壳层4p电子激发的双电子复合速率数对总双电子复合速率系数有很重要的贡献,而4s电子激发对总双电子复合速率数贡献小于7.5%。给出了△n=0,1和2三类芯激发对总双电子复合速率系数的贡献以及自由电子俘获到不同主量子数的双电子复合速率系数,发现△n=2的芯激发和n'>15的DR速率系数对总DR速率系数的贡献也很重要。进一步给出了△n=0,1和2三类芯激发和总DR速率系数的拟合参数,拟合结果和计算值符合,偏差小于1%。通过对双电子复合、辐射复合以及三体复合速率系数的比较得知,在温度高于1 eV时,DR过程是Xe8+离子的主要复合过程。

Based on the fully relativistic configuration interaction method, theoretical calculations are car- ried out for the dielectronic recombination （DR） rate coefficients of Xe8＋ ions in the temperature region from 0.1 to 1 650 eV. The comparison of the DR rate coefficients from 4s, 4p and 4d subshell excitations shows that 4d subshell excitation dominates in the whole temperature region. The contribution from 4p subshell excitation is very important at temperature above 10 eV and the contributions from 4s subshell ex- citation is lower than 7.5% in the whole temperature region. Similarly, the comparison of the DR rate co- efficients through △n= 0, I and 2 core excitation shows that the contribution from △n= 2 core excitation can not be neglected, the contributions from n＇〉15 can also not be neglected. The DR rate coefficients of △n=0, 1 and 2 core excitation and the total DR rate coefficients are fitted with some parameters, which are in good agreement with theoretical calculations values （within 1 % difference）. The total DR rate coef- ficients are greater than radiative recombination （RR） and three-body recombination （TBR） rate coeffi- cients at temperature above 1 eV. Therefore, the DR process can strongly influence the ionization balance of laser produced xenon plasmas.