Detailed level-by-level study of dielectronic recombination for Ne-like gold

Ab initio calculation of the dielectronic recombination (DR) rate coefficient for Ne-like gold in the ground state 2s 2 2p 6 is performed. The value of DR rate coefficient has been calculated over a wide temperature range from 1 to 10 5 eV. The present level-by-level calculations include the contributions of all the levels belonging to the following Na-like doubly excited configuration complexes, namely, 2s 2 2p 5 3 ln ′ l ′, 2s 1 2p 6 3 ln ′ l ′ ( n ′⩽12, l ′⩽8), 2s 2 2p 5 4 ln ′ l ′, 2s 1 2p 6 4 ln ′ l ′ ( n ′=4, 5) and 1s 1 2s 2 2p 6 3 l 3 l ′. There are 18 853 doubly excited levels in all these complexes. The contributions of 2s 2 2p 5 3 ln ′ l ′ and 2s 1 2p 6 3 ln ′ l ′ for n ′>12 are evaluated by applying the complex-by-complex n ′ −3 extrapolation method, which are found to represent at most 3 and 0.04% of the total DR rate coefficient, respectively. The contribution of complex series 2s 2 2p 5 3 ln ′ l ′ is a little more than 90% to the total DR rate coefficient. The contributions of 2s 1 2p 6 3 ln ′ l ′, 2s 2 2p 5 4 ln ′ l ′ and 2s 1 2p 6 4 ln ′ l ′ complexes are about 2, 6 and 1%, respectively. The DR contributions of 2s 2 2p 5 3 ln ′ l ′ and 2s 1 2p 6 3 ln ′ l ′ complexes with l ′>6 are found to be negligible (about 0.6 and 0.8%). For complex series 2s 2 2p 5 3 ln ′ l ′, the dominant contribution comes from the lowest complex 2s 2 2p 5 3 l 3 l ′ at all temperatures. For complex series 2s 1 2p 6 3 ln′l ′, the dominant contribution comes from the 2s 1 2p 6 3 l 3 l ′ complex at low and medium electron temperature ( kT e 10 keV) the contribution of 2s 1 2p 6 3 l 4 l ′ complex becomes larger. For complex series 2s 2 2p 5 4 ln ′ l ′ and 2s 1 2p 6 4 ln ′ l ′, the contribution from n ′=5 complex exceeds the contribution from n′ =4 complex at about 2000 eV. The effects of radiative decays to autoionizing levels possibly followed by radiative cascades (DAC) are checked for the (2s2p) 7 3 l 3 l ′ and (2s2p) 7 3 l 4 l ′ complexes and found to be negligible. The total DR rate coefficient is fitted to an empirical formula.