Dielectronic recombination of Ne-like tungsten

Abstract

Relativistic calculations of the dielectronic recombination (DR) cross section and rate coefficient for Ne-like tungsten $({\mathrm{W}}^{64+})$ in the ground state ${2s}^{2}{2p}^{6}$ are performed. The DR contributions of the most important Na-like doubly excited configuration complexes, namely, ${(2s2p)}^{7}{3ln}^{\ensuremath{'}}{l}^{\ensuremath{'}}$ ${(n}^{\ensuremath{'}}=3--13)$ and ${(2s2p)}^{7}{4l4l}^{\ensuremath{'}},$ are calculated by level-by-level computations. Collisional transitions following the initial electron capture are neglected. The total DR cross section is presented in the form of 5-eV-wide peaks for the purpose of revealing the detailed atomic level structure, and in the form of 50-eV-wide peaks for the purpose of comparison with planned electron-beam experiments. The ${(2s2p)}^{7}{3l3l}^{\ensuremath{'}}$ complex is found to provide the dominant DR channel. The sum of the DR contributions of the ${(2s2p)}^{7}{3ln}^{\ensuremath{'}}{l}^{\ensuremath{'}}$ configurations with ${n}^{\ensuremath{'}}>13,$ evaluated by applying the complex-by-complex ${n}^{\ensuremath{'}\ensuremath{-}3}$ extrapolation method, is found to represent at most 3% of the total DR rate coefficient. The DR contribution of ${(2s2p)}^{7}{3ln}^{\ensuremath{'}}{l}^{\ensuremath{'}}$ configurations with ${l}^{\ensuremath{'}}>5$ is found to be negligible (about 0.1%). The total DR rate coefficient is fitted to a convenient analytical expression which reproduces the original data with an accuracy of about 2% or better within a very wide electron temperature range.