Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster: New Instruments and Methods

CPP 15.7: Poster

Dienstag, 27. März 2012, 18:15–20:15, Poster A

A sample holder for soft x-ray absorption spectroscopy of liquids in transmssion mode — •Simon Schreck, Gianina Gavrila, Christian Weniger, and Philippe Wernet — Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin, Germany

Applying soft x-rays to liquids is challenging due to the incompatibility of the vacuum environment required for soft x-rays and the high vapor pressure of liquids. When recording soft x-ray absorption spectra in transmission mode, which is the most direct and efficient way, the strong attenuation of soft x-rays in matter calls for ultrathin samples.

Here we present a novel sample holder for soft x-ray absorption spectroscopy of liquids in transmission mode based on sample cells with x-ray transparent silicon nitride membranes. The sample holder allows for a reliable preparation of ultrathin liquid films with an adjustable thickness in the nm-µm range. This enables measurements of high quality x-ray absorption spectra of liquids in transmission mode, as will be shown for the example of liquid H2O, aqueous solutions of 3d-transition metal ions and alcohol-water mixtures. The fine structure of the x-ray absorption spectra is not affected by the sample thickness. No effects of the silicon nitride membranes were observed in the spectra. It is shown how an inhomogeneous thickness of the sample affects the spectra and how this can be avoided.

The measurements were performed at the synchrotron radiation source BESSYII at the Helmholtz-Zentrum Berlin.