The Use of Polymer Thin Films as Transmissive Sample Supports in Xuv Spectroscopy

Abstract

We discuss current challenges in the preparation of thin film samples for extreme ultraviolet (XUV) spectroscopy, and offer alternative methods which now enable this spectroscopy to be performed on a wide variety of previously inaccessible compounds. We explored the production, characterization, and use of polymer thin films as highly XUV transmissive sample supports, finding that such thin films could be made via a "slip-coating" technique in which polymer solution is deposited from the shearing meniscus between parallel sliding glass plates. Films made from polystyrene or polyvinyl chloride are thin (10 2 -10 3 nm), homogeneously flat, smooth, and transmit more XUV light than do silicon nitride windows. The analytes of interest are directly cast upon the polymer surface, or codeposited from a common solution. In demonstration of the suitability of these methods towards XUV spectroscopy, we prepared samples of eight different first-row transition metal complexes and report their respective M-edge XANES spectra in the range of 40-90 eV. We additionally report the excited state difference spectrum of Fe(bpy) 3 Cl 2 at 1.5 ps after visible excitation.