Relativistic multireference many-body perturbation theory for open-shell ions with multiple valence shell electrons: the transition rates and lifetimes of the excited levels in chlorinelike Fe X

Abstract

A recently developed relativistic multireference many-body perturbation theory based on multireference configuration-interaction wavefunctions as zeroth-order wavefunctions is outlined. The perturbation theory employs a general class of configuration-interaction wavefunctions as reference functions, and thus is applicable to multiple open valence shell systems with near degeneracy of a manifold of strongly interacting configurations. Multireference many-body perturbation calculations are reported for the ground and excited states of chlorinelike Fe X in which the near degeneracy of a manifold of strongly interacting configurations mandates a multireference treatment. Term energies of a total of 83 excited levels arising from the 3s23p5, 3s3p6, 3s23p43d, 3s3p53d, and 3s23p33d2 configurations of the ion are evaluated to high accuracy. Transition rates associated with E1/M1/E2/M2/E3 radiative decays and lifetimes of a number of excited levels are calculated and compared with laboratory measurements to critically evaluate recent experiments.