Absorption and scattering of photons by bound electrons

Absorption and elastic scattering of photons by bound electrons is studied within the independent-particle-approximation. Generally a self-consistent potential with Latter tail correction is used, which could cause additional unphysical structures in predicting for atomic processes. Better alternative approaches are discussed. In addition to the neutral and ground state case, we study these processes for ions of various degree of ionization and atoms in the environment of high temperature and high density plasmas. Photoionization is a first order process in the photon electron interaction. Here the author studies photoionization for ions of various degree of ionization of an isonuclear sequence for various elements and photon energies. The subshell cross sections generally (but not always) increase as degree of ionization increases, the number of electrons decreases; due to these two countervailing factors the total cross section can increase or decrease as degree of ionization increases. In the high energy case, the total cross section generally increases as p-, d- and f-shell electrons are removed but decreases as s shell electrons are removed. A semi-quantitative analytic approach is given to explain this effect. Cooper minima in photoionization occur when, at a certain photon energy, the matrix element of a given transition channel is zero. The trajectories of the energy positions of the Cooper minima as a function of the quantum defect difference of initial and final states, is studied and discussed in terms of wavefunction overlap in regions of the lobes which dominate the matrix elements. In the high temperature, high density plasma environment the author also studies second order photon electron interaction processes: Rayleigh scattering, the elastic scattering of photons off bound atomic electrons