Double-excited narrow autoionization states of ytterbium atom

Study of spectra for lanthanides atoms with relativistic many- body perturbation theory: Rydberg resonances

“…A model relativistic energy approach in a case of the multielectron atom has been proposed by Ivanov-Ivanova et al [6][7][8] and its generalized gauge-invariant version has been developed in Refs. [9][10][11][12].…”

“…In the theory of the non-relativistic atom a convenient field procedure is applied for calculating the energy shifts ΔE of degenerate states. This procedure is connected to secular matrix M diagonalization [7,8]. In constructing M, the Gell-Mann and Low adiabatic formula for ΔE is used.…”

“…The non-relativistic secular matrix elements are expanded in a Perturbation Theory (PT) series for the interelectron interaction. The complex secular matrix M is represented in the form [7,8]:…”

“…The excited states of the ytterbium atom can be treated as the states with two-quasiparticles above the electron core [Xe]4f 14 . Within the standard energy approach [8][9][10][11], the autoionization width is determined by the square of an electron interaction matrix element having the form: The real part of the electron interaction matrix element is determined using expansion in terms of Bessel functions [17][18][19]26]:…”

“…[1][2][3][4] and references therein). Relativistic many-body perturbation theory is effectively applied to the computation of spectra of low-lying states for lanthanides atoms [5][6][7][8][9][10].…”