By using X-ray Absorption Spectroscopy (XAS) the unoccupied electronic states of a sample can be probed. Fingerprinting the chemical binding, these states reveal information about their interaction with the environment. In XAS electrons are excited via X-ray and the total resulting fluorescence is analyzed in dependence on the excitation energy.
The LIQUIDROM setup allows the investigation of samples in liquid phase and solutions with soft X-rays. This is particularly challenging, since soft X-ray are absorbed in air whereas liquids evaporate in vacuum. In order to bridge this pressure gap, special provisions have to be made. One way is the use of a flowcell with a thin membrane for irradiation of the sample.Measuring a flowing sample provides the additional advantage to avoid radiation-induced sample damage. Another method is to substitute the air by an inert helium atmosphere, in which the absorption is reduced considerably. This allows the investigation of liquid films on surfaces and aerosols in normal pressure.