Abstract: The formation of nanoparticles under the irradiation of a thin metallic gold film by accelerated atomic and molecular ions is demonstrated. The obtained structures are used to form porous silicon by the metal-assisted chemical etching. The size of the gold nanoparticles and structure of porous silicon greatly depend on the type of incident particles and their fluence. A local increase in the density of energy released at the target surface under molecular ion bombardment significantly reduces the doses required to form the desired film morphologies and spread of nanoparticles over the surface and simultaneously makes a weaker radiative impact on the substrate. The shape of the fluorescence and fluorescence-excitation spectra of porous silicon obtained from the irradiated structures is independent of the irradiation parameters, but changes with the etching-solution concentration.