The functionality of a new version of the National Institute of Standards and Technology database Simulation of Electron Spectra for Surface Analysis (SESSA) has been extended by implementing a new geometry engine. The engine enables users to simulate Auger-electron spectra and X-ray photoelectron spectra for different predefined morphologies (planar, islands, spheres, multi-layer core-shell particles). We compared shell thicknesses of core-shell nanoparticles derived from core-shell XPS peak intensities using Shard-s method, which allows one to estimate shell thicknesses of core-shell nanoparticles, and a series of SESSA simulations for a wide range of nanoparticle dimensions. We obtained very good agreement of the shell thicknesses for cases where elastic scattering within the shell can be neglected, a result that is in accordance with the underlying assumptions of the Shard model. If elastic-scattering effects are important, there can be thickness uncertainties of up to 25 %. Based on the newly implemented geomtry engine, various systems of core-shell nanoparticles were simulated. It was studied how the angle-resolved core-to-shell photoelectron intensity ratio changed with increasing periodicity of the core-shell nanoparticles. The study entailed single-layered systems of core-shell particles ranging from dispersed structures with a low surface coverage to perfectly aligned arrangements. It was found that with increasing periodiciy of the structure features in the angle-resolved XPS spectra emerge, which can be explained be shadowing effects of adjacent core-shell particles. Also, various powder-like structures of core-shell particles were studied to investigate the validity of the single-sphere model for core-shell particles. The results show that the model correctly reproduces the peak intensities of core-shell particles, but more detailed modeling is needed to describe the inelastic background. Furthermore, experimental spectra of functionalized gold nanoparticles obtained by Techane et al. were analyzed with SESSA 2.0, both with respect to the relevant peak intensities as well as the spectral shape. Good agreement between experiment and theory was found for both cases.