[en] The focus of this thesis is the inclusion of the Breit interaction in the scattering matrix elements for calculating electron impact excitation cross sections or collision strengths. It is intended to determine the range of conditions for which the Breit excitation has avoided such a thorough analysis. A review of the theory of relativistic electron impact excitation is provided. The method of calculation is a fully relativistic distorted-wave approach equivalent to first-order time-dependent perturbation theory. The perturbation is taken to be the sum of the Coulomb and Breit interactions between the free and bound electrons. The required bound state wavefunctions and energies are calculated with a relativistic Hartree-Fock-Slater or Dirac-Fock-Slater method. The approximations in these two methods require the atomic number of the target ion to be at least twice its number of bound electrons if accurate results are to be obtained. Only highly ionized ions are considered. Collision strengths are presented for H-like, He-like, and Li-like ions with atomic numbers Z = 26, 54, and 92. Several kinds of transitions and impact electron energies are also considered. These data indicate that all three forms of the Breit interaction considered in this research can have significant effects on the excitation collision strengths. Effects range from as much as nearly 30% for Z = 54 up to nearly 70% for Z = 92 in transitions involving the tightest bound 1s electron. These large effects are exhibited for the three types of ions listed above and persist over a range of electron energies. It is expected that the present data will be useful to those researchers specializing in high temperature plasma modeling or plasma diagnostics. This data may also be used to compare with and interpret future results of electron beam ion trap experiments

[en] Recent work is extended to include a factorized version of the generalized Breit interaction in the scattering matrix elements for electron impact excitation of highly charged ions. A general expression for the interaction, applicable to any ion stage, is derived from the factorization method of Bar-Shalom, Klapisch and Oreg. The resulting formula gives the collision strength as the usual sum over states of a product of an angular piece and a radial piece which can be interpolated as a function of transition energy. Collision strengths are calculated with a relativistic distorted-wave method and results for previously unpublished ion stages are presented

[en] Relativistic distorted wave collision strengths are given for the 21 transitions among the 4s_1/2, 4p_1/2, 4p_3/2, 4d_5/2, 4f_7/2 levels and for the 63 transitions from these levels to the excited levels nlj with n = 5 in the 33 Cu-like ions with nuclear charge number Z in the range 60 ≤ Z ≤ 92. The calculations were made for the six final, or scattered, electron energies E' = 0.001, 0.005, 0.015, 0.04, 0.09, and 0.18, where E' is in units of Z²_eff rydbergs with Z_eff = Z - 23.2. In addition, the transition energies and electric dipole oscillator strengths are given. To their knowledge the present work is the first publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged Cu-like ions

[en] Relativistic distorted wave collision strengths are given for the 10 transitions among the 3s_1/2, 3p_1/2, 3p_3/2, 3d_3/2, and 3d_5/2 levels and for the 80 transitions from these levels to the excited levels nlj with n = 4 and 5 in the 71 Na-like ions with nuclear charge number Z in the range 22 ≤ Z ≤ 92. The calculations were made for the six final, or scattered, electron energies E' = 0.0025, 0.015, 0.04, 0.10, 0.21, and 0.40, where E' is in units of Z²_eff rydbergs with Z_eff = Z - 8.34. In addition, the transition energies and electric dipole oscillator strengths are given. To their knowledge the present work is the first comprehensive publication of the results of fully relativistic calculations of the collision strengths for excitation of Na-like ions

[en] Relativistic distorted wave collision strengths are given for the 3 transitions among the 2s_1/2, 2p_1/2, and 2p_3/2 levels and for the 63 transitions from these levels to the excited levels nlj with n = 3, 4, and 5 in the 85 Li-like ions with nuclear charge number Z in the range 8 ≤ Z ≤ 92. The calculations were made for the six final, or scattered, electron energies E' = 0.008, 0.04, 0.10, 0.21, 0.41, and 0.75, where E' is in units of Z²_eff rydbergs with Z_eff = Z - 1.66. In addition, the transition energies and electric dipole oscillator strengths are given. To their knowledge the present work is the first comprehensive publication of the results of fully relativistic calculations of the collision strengths for excitation of Li-like ions

[en] An overview will be given of the recent progress made in computing atomic data for elements relevant to magnetic fusion and astrophysics using the Los Alamos suite of atomic physics codes. A recent paper has described the electron-impact excitation and ionization cross sections that were computed for all ion stages of Si, Cl, and Ar. Another recent study computed all excitation and ionization processes (in the configuration-average approximation) for all ion stages of fifteen elements that are found in the solar corona. These data were used to compute the radiative losses of the Sun for a range of astrophysical conditions. Both of these projects will be discussed at the meeting. (author)

[en] Relativistic distorted-wave collision strengths have been calculated for the three transitions among the three levels with a hole in the n = 2 shell and for the 327 transitions from these levels to the excited levels with two holes in the n = 2 shell and one electron in the n = 3 shell in all the 71 F-like ions with nuclear charge number Z in the range 22 ≤ Z ≤ 92. The results are given here for a sample of 18 values of Z. The calculations were made for the six final, or scattered, electron energies E' = 0.008, 0.04, 0.10, 0.21, 0.41, and 0.75, where E' is in units of Z_eff² rydbergs with Z_eff = Z -6.667. In addition, the transition energies and electric dipole oscillator strengths are given. To the authors knowledge the present work is the first comprehensive publication of the results of fully relativistic calculations of the collision strengths for excitation of F-like ions

[en] Relativistic distorted-wave collision strengths are given for the 248 possible transitions from the ground level to the excited levels with n = 4 and 5 in the 33 Ni-like ions with nuclear charge number Z in the range 60 much-lt Z much-lt 92. The calculations were made for the six final, or scattered, electron energies E' = 0.002, 0.01, 0.03, 0.07, 0.15, and 0.28, where E' is in units of Z_eff² rydbergs with Z_eff = Z - 22.5. In addition, the transition energies and electric dipole oscillator strengths are given. To the authors knowledge the present work is the first comprehensive publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged Ni-like ions

[en] We review the first 'virtual workshop' designed to compare NLTE emissivities produced by widely differing types of atomic physics codes. A small set of significant results, illustrating the progress that is still to be achieved, is presented. We conclude with some lessons learned and possible avenues for future progress

[en] This paper discusses the development of the ATOMIC code, a new low to mid Z opacity code, which will replace the current Los Alamos low Z opacity code LEDCOP. The ATOMIC code is based on the FINE code, long used by the Los Alamos group for spectral comparisons in local thermodynamic equilibrium (LTE) and for non-LTE calculations, both utilizing the extensive databases from the atomic physics suite of codes based on the work of R.D. Cowan. Many of the plasma physics packages in LEDCOP, such as line broadening and free-free absorption, are being transferred to the new ATOMIC code. A new equation of state (EOS) model is being developed to allow higher density calculations than were possible with either the FINE or LEDCOP codes. Extensive modernization for both ATOMIC and the atomic physics code suites, including conversion to Fortran 90 and parallelization, are underway to speed up the calculations and to allow the use of expanded databases for both the LTE opacity tables and the non-LTE calculations. Future plans for the code will be outlined, including considerations for new generation opacity tables.