Hartree-Fock-Roothaan-Rechnungen für Vielelektronen-Atome in Neutronenstern-Magnetfeldern

Abstract

The interpretation of thermal neutron star spectra requires extensive data sets of atomic dipole transitions in intensive magnetic fields. For this purpose, the new HFFER method for the fast computation of wave functions, energies, and oscillator strengths of medium-Z atoms and ions at neutron star magnetic field strengths B>10^7 T is developed in this thesis. The coupled system of Hartree-Fock equations is solved self-consistently with longitudinal wave functions and transversal amplitudes of Landau states up to n=7. In the presented ab-initio procedure the transversal Landau amplitudes are computed by solving the Hartree-Fock-Roothaan equations for each electron. The longitudinal wave functions result from the system of one-dimensional Hartree-Fock equations, which are solved by the finite element method in an apropriate B-spline basis. All algorithms can be implemented in an highly efficient parallel way on a computer cluster. Typically an iron ground state with N=26 electrons is computed on p=N=26 cluster processors using less than 500 seconds of run-time. Numerical calculations are presented for ground states, and different excited states of atoms and ions for nuclear charges Z=2,...,26 and N=2,...,26 electrons. If possible, the new results are compared with previous adiabatic calculations on the one hand, and recent quantum Monte Carlo simulations on the other.