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

Abstract

Ab initio calculation of the dielectronic recombination (DR) rate coefficient for Ne-like gold in the ground state 2s22p6 is performed. The value of DR rate coefficient has been calculated over a wide temperature range from 1 to 105 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, 2s22p53ln′l′, 2s12p63ln′l′ (n′⩽12, l′⩽8), 2s22p54ln′l′, 2s12p64ln′l′ (n′=4, 5) and 1s12s22p63l3l′. There are 18 853 doubly excited levels in all these complexes. The contributions of 2s22p53ln′l′ and 2s12p63ln′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 2s22p53ln′l′ is a little more than 90% to the total DR rate coefficient. The contributions of 2s12p63ln′l′, 2s22p54ln′l′ and 2s12p64ln′l′ complexes are about 2, 6 and 1%, respectively. The DR contributions of 2s22p53ln′l′ and 2s12p63ln′l′ complexes with l′>6 are found to be negligible (about 0.6 and 0.8%). For complex series 2s22p53ln′l′, the dominant contribution comes from the lowest complex 2s22p53l3l′ at all temperatures. For complex series 2s12p63ln′l′, the dominant contribution comes from the 2s12p63l3l′ complex at low and medium electron temperature (kTe<10 keV), while at higher electron temperature (kTe>10 keV) the contribution of 2s12p63l4l′ complex becomes larger. For complex series 2s22p54ln′l′ and 2s12p64ln′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)73l3l′ and (2s2p)73l4l′ complexes and found to be negligible. The total DR rate coefficient is fitted to an empirical formula.