  We present a detailed quantum mechanical non empirical DFT investigation of
the energy-optimized geometries, phase stabilities and electronic properties of
bulk Pt3N, PtN and PtN2 in a set of twenty different crystal structures.
Structural preferences for these three stoichiometries were analyzed and
equilibrium structural parameters were determined. We carefully investigated
the band-structure and density of states of the relatively most stable phases.
Further, GW_0 calculations within the random-phase approximation (RPA) to the
dielectric tensor were carried out to derive their frequency-dependent optical
constants of the most likely candidates for the true crystal structure.
Obtained results were comprehensively compared to previous calculations and to
experimental data.
