We present the results of a combined experimental (neutron scattering) and theoretical (computer simulation) effort to investigate structural properties of polycarbonate melts and glasses in the wave vector regime of Q less than or equal to 2.2 Angstrom(-1). The experimental part consists of advanced spin polarized scattering experiments, allowing us to extract the coherent scattering for protonated and deuterated samples. The simulations employ recently developed novel mapping procedures, which allow us to efficiently equilibrate complex polymer melts, thereby reproducing the experiment in much closer detail than earlier attempts.