Two-electron and one-photon transitions in highly charged nickel-like ions

This paper calculates the transition wavelengths and probabilitiesof the two-electron and one-photon (TEOP) transition from the$(3{rm s}^{-1}_{1/2}4{rm d}_{j})_{J=1,2}$ to $(3{rmp}^{-1}_{3/2}4{rm s}_{1/2})_{J=1}$ and the $(3{rmp}^{-1}_{1/2}4{rm s}_{1/2})_{J=1}$ to $(3{rm d}^{-1}_{j}4{rmd}_{j'})_{J=1,2}$ for highly charged Ni-like ions with atomic number$Z$ in the range $47leq Zleq92$. In the calculations, themulti-configuration Dirac--Fock method and corresponding programpackages GRASP92 and REOS99 were used, and the relativistic effects,correlation effects and relaxation effects were consideredsystematically. It is found that the TEOP transitions are verysensitive to the correlation of electrons, and the probabilitieswill be enhanced sharply in some special $Z$ regions along theisoelectronic sequence. The present TEOP transition wavelengths arecompared with the available data from some previous publications,good agreement is obtained.