类氖等电子系列离子基态的双电子复合速率系数研究

使用全相对论组态相互作用方法, 能级-能级细致计算了0.1 E_I ≤ kT_e≤ 10 E_I (E_I是类钠离子基态的第一电离能) 温度范围内类氖离子基态双电子复合(DR)速率系数, 双激发自电离能级考虑了(2s2p)⁷3ln'l', (2s2p)⁷4l4l' 以及(2s2p)⁷4l5l'组态. 对于(2s2p)⁷3ln'l'双激发自电离组态, 轨道角量子数l' >8 的(2s2p)⁷3ln'l'双激发自电离态对双电子复合速率系数的贡献可以忽略不计; (2s2p)⁷3ln'l'双激发自电离组态的高里德堡态对双电子复合速率系数的贡献满足 n'^-3组态-组态外推法, 并且核电荷数越大, 趋于n'^-3标度的n'值越小; 对细致能级计算得到的类氖离子基态的总DR速率系数进行了拟合, 得到类氖离子基态的总DR速率系数随核电荷数 Z和电子温度变化的经验公式, 该拟合公式与细致计算结果的偏差在2%以内, 能较准确的计算任意核电荷数Z的类氖离子在0.1E_I ≤ kT_e ≤ 10E_I电子温度范围的DR速率系数. Burgess-Merts(BM)近似公式不适用于估算低温(kT_e<0.3 E_I)类氖离子的DR速率系数, 在高温(kT_e>2E_I)时, 类氖离子的DR速率系数可以用BM近似公式表示.

The study of dielectronic recombination (DR) rate coefficient for ground state of Ne-like isoelectronic sequence ions

The dielectronic recombination (DR) rate coefficients for Ne-like isoelectronic sequence ions in the ground state 2s²2p⁶ are calculated by using relativistic configuration interaction (RCI) method over a wide temperature ranging from 0.1E_I to 10E_I where E_I is the ionization energy of corresponding Na-like ion. The (2s2p)⁷3ln'l', (2s2p)⁷4l4l' and (2s2p)⁷4l5l' complexes are considered as autoionizing doubly excited states of Ne-like ions in the calculation. The contribution of (2s2p)⁷3ln'l' complex with l' >8 is found to be negligible. The contribution of high Rydberg states of (2s2p)⁷3ln'l' complex obeys the complex-complex n'^-3 extrapolation, and the larger the nuclear charge, the smaller the value of n' is. On the basis of the detailed level-by-level results, a general analytic formula for the total DR rate coefficient for all the ions along the Ne-like isoelectronic sequence is constructed. This formula can generally reproduce the calculated DR rate coefficients within 2% for electron temperature between 0.1E_I and 10E_I. Burgess-Merts semiempirical formula is found to be inadequate for predicting the DR rates of Ne-like ions at low electron temperatures (kT_e<0.3E_I) and may be used for high electron temperatures (kT_e > 2E_I).