Rostock 2019 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 8: XUV and X-ray Excitation and Spectroscopy

MO 8.5: Vortrag

Montag, 11. März 2019, 17:15–17:30, S HS 001 Biologie

Interrogating the Electronic Structure of Aqueous Diazines Using Non-Resonant and Resonant Soft X-ray Photoelectron Spectroscopy — •Md Sabbir Ahsan^1,2 and Iain Wilkinson¹ — ¹Methods for Material Development, Helmholtz-Zentrum Berlin, Hahn Meitner platz 1, 14109 Berlin, Germany — ²Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

Diazines play important roles in determining the photophysicochemical properties of bio-molecules such as DNA and RNA. We will present the electronic structure study of aqueous (aq.) diazines using liquid-microjet-based x-ray photoelectron spectroscopy (XPS). Valence band (HOMO) and core level C 1s and N 1s BE’s are red shifted in aq. solution in comparison to the gas-phase. Preliminary surface- and bulk-sensitive studies on pyrimidine highlight an increase of N 1s BE’s in the bulk compared to at the vacuum/liquid interface, whereas the C 1s spectra show the opposite behavior. Pyrimidine shows the lowest N 1s BE among the diazines in the surface-sensitive measurements. Moreover, resonant photoelectron spectroscopy (RPES) scans over the diazine N K-edges were recorded to study local and non-local relaxation processes in aq. solution. A number of core-valence resonances were identified and were found to be blue shifted compared to isolated gas phase molecules. Our study highlights solvent-induced electronic structure perturbations which are expected to provide information about the intra and intermolecular energy and proton transfer processes occurring in aq. diazine solutions following x-ray excitation.