The present PhD thesis contains two parts which are both related to the domain of X-ray and inner-shell atomic physics. The first part consists in a detailed investigation of the photoinduced X-ray emission of liquid mercury, while the second one concerns the radiative decay of hollow K-shell atoms bombarded by heavy ions.

The K-, L- and M-shell X-ray fluorescence of liquid Hg was measured in high energy resolution using the Laue-type DuMond and Bragg-type von Hamos spectrometers of Fribourg. A set of 32 transitions was measured. The energies, Lorentzian widths and intensities of the lines were determined from the fits. Furthermore, solving by means of a least-squares-fit method the two linear systems of simultaneous equations built on the obtained transition energies and transition widths, the binding energies and natural widths of most core-levels of Hg could be deduced.

The second subject investigated in this PhD concerns the radiative decay of hollow K-shell atoms. In this project, we have investigated the radiative decay of double K-shell vacancy states produced in solid Ca, V, Fe and Cu targets by impact with about 10 MeV/amu C and Ne ions. The K hypersatellite X-ray lines were measured with the von Hamos crystal spectrometer of Fribourg. From the fits of the X-ray spectra, the energies, line widths and relative intensities of the hypersatellite lines could be determined. The first aim of the project was to determine the single-to-double K-shell ionization cross sections for the 8 investigated collisions. The cross section ratios were deduced from the corrected relative intensities of the hypersatellites. They were compared to ratios calculated from the SCA model and from CTMC calculations.