Soft X-ray spectroscopy of liquids: Development and characterization of a flat jet nozzle system with experimental applications

In this thesis, I report the development and implementation of 3D-printed flat sheet nozzles for advancing liquid-phase soft X-ray spectroscopy at MAX IV Laboratory in Paper II. The nozzles presented here, discussed in Paper III, were custom designed for the FlexPES beamline and deliver flat liquid sheets of micrometer thickness. The planar shape of the liquid leaf generated with these nozzles serves to significantly simplify the measurement geometry, allowing a more accurate interpretation of experimental results. In addition, I also demonstrate, that these significantly thinner sheets facilitate transmission-mode X-ray absorption measurements, thus expanding experimental capabilities for liquid jet users at MAX IV.To demonstrate the type of experiments that could benefit from the use of flat sheet nozzles, we studied the impact of angular distribution on X-ray photoelectron spectroscopy (XPS) data from aqueous solutions. The study comprises two parts: In paper I, the angular distribution of N 1s photoelectrons from an aqueous ammonium nitrate solution was investigated using a cylindrical microjet and the surface propensity of the solute ions in the same sample was investigated using a liquid flat jet. In paper IV, we investigated the angular effects observed in photoelectron spectra recorded for a range of potassium carboxylate aqueous solutions. In particular, we explored how molecular orientation, influenced by alkyl chain length, affects the observed X-ray photoelectron spectra.