Effects of partial ionization in magnetized neutron star atmospheres

This thesis presents the development of a routine to incorporate magnetically induced partial ionization into neutron star atmosphere models. A dataset of opacities computed by the model of Potekhin and Chabrier (Potekhin and Chabrier [2004]), which accounts for partial ionization, was adapted for use within the completely ionized, hydrogen/helium atmosphere frame work of Lloyd (Lloyd [2003]). The dataset, originally provided for a fixed surface magnetic field of B = 10^13.7 G, was modified to include both photon polarization modes with explicit angular dependence, interpolated onto the fixed photon energy grid of the Lloyd model, and extended with a two-dimensional interpolation scheme to allow opacity evaluation at arbitrary temperature and density values. The resulting implementation enables the direct computation of opacities with partial ionization using input parameters identical to the native model. The two opacity sets were compared, allowing for a first assessment of the effects of partial ionization within the Lloyd atmosphere framework.