Configuration interaction and radiative decay rates in trebly ionized tungsten (W IV)

Abstract

Radiative decay rates are obtained for the first time for allowed (E1) and forbidden (M1, E2) transitions in trebly ionized tungsten (W IV). Our calculations, motivated by strong interest for low-density plasmas and fusion research, illustrate in a convincing way the importance of core-valence correlation effects which substantially increase the lifetimes and, accordingly, decrease the transition probabilities of this heavy ion. Due to the lack of experimental data for W IV, the reliability of the theoretical 'f' values can only be tested by comparison of numerical results obtained with two independent (i.e. multiconfiguration Dirac-Fock and relativistic Hartree-Fock with core-polarization effects (HFR+CPOL)) methods well suited for investigating the atomic structure of heavy ions.

Relativistic many-body calculations of excitation energies, oscillator strengths, transition rates, and lifetimes in samariumlike ions

“…Recently, configuration interaction and radiative decay rates in triply ionized tungsten (W IV) was investigated in Ref. [23]. Numerical results for the first excited configurations (5d 2 6s, 5d6s 2 , 5d 2 6p, and 5d6s6p) were obtained with two independent [i.e., multiconfiguration Dirac-Fock and relativistic Hartree-Fock with core-polarization effects (HFR + CPOL)] methods.…”

Overview of recent advances performed in the study of atomic structures and radiative processes for the lowest ionization stages of heavy elements

“…In this context, the new sets of atomic data obtained in our work for the first ionization stages of tungsten (W I, W II, and W III) [104][105][106][107] will be extremely useful for future fusion plasma analyses. As an extension of these studies, radiative decay rates have been obtained recently for allowed (E1) and forbidden (M1, E2) transitions in Lu-like (W IV), Yb-like (W V), Tm-like (W VI), and Ho-like (W VIII) tungsten [108][109][110][111]. The latter investigations were carried out with the HFR + CPOL + CPEN method in which the radial energy parameters were optimized semi-empirically using the most recent experimental energy levels available (ref.…”

Metastable level properties of the excited configuration 4p64d84f

“…Traditionally, the radiative lifetimes for the excited metastable levels of the ground configuration are determined from the calculated electric quadrupole (E2) and magnetic dipole (M1) transition probabilities, see [3,9,10,11]. These types of radiative transitions also can be important when the radiative lifetimes of the levels of excited configurations are calculated [1,6,5]. Very recently the multiconfiguration Dirac-Hartree-Fock approach was applied to determine the E1, M1, E2, and M2 transition parameters for the ions up to Z = 36 (see [12,13] and the references therein).…”

“…Metastable levels, which do not have the electric dipole decay channels, are essential in study of both astrophysical and laboratory plasmas [2,3,4] or in analysis of experimental spectra of various ions [6,7], including very important tungsten ions (see, e.g., [4,5,8]). As it was concluded in [2], the parameters of high multipole order radiative transitions and the radiative lifetimes of metastable levels were "essential building blocks in radiative-collisional models simulating spectra".…”