2013/05/15 by Thorsten Kersting, Damir Zajec, Kersting, Thorsten +5
Physics and Astronomy · #Atomic Physics (physics.atom-ph) #Atomic and Molecular Physics #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Solar and Space Plasma Dynamics #physics.atom-ph
paper · pdf · doi:10.48550/arxiv.1305.3454
13 pages, 10 figures, submitted at APJ
openalex publication_date 2013/05/15 · arxiv created 2013/08/07 · arxiv updated 2013/08/08 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We derive the photoionisation cross section in dipole approximation for many-electron atoms and ions for neutron star magnetic field strengths in the range of 107 to 109 T. Both bound and continuum states are treated in adiabatic approximation in a self-consistent way. Bound states are calculated by solving the Hartree-Fock-Roothaan equations using finite-element and B-spline techniques while the continuum orbital is calculated by direct integration of the Hartree-Fock equations in the mean-field potential of the remaining bound orbitals. We take into account mass and photon density in the neutron star's atmosphere, finite nuclear mass as well as thermal occupation of the levels. The data may be of importance for the quantitative interpretation of observed x-ray spectra that originate from the thermal emission of isolated neutron stars. They can serve as input for modeling neutron star atmospheres as regards chemical composition, magnetic field strength, temperature, and redshift. Our main focus in this paper lies on helium and helium-like oxygen. These two-electron systems are simple enough to calculate all possible transitions when limiting the quantum numbers and should show all the basic structures and behaviour of other two-electron systems up to iron.