TY - JOUR A1 - Eckert, Sebastian A1 - Beye, Martin A1 - Pietzsch, Annette A1 - Quevedo, Wilson A1 - Hantschmann, Markus A1 - Ochmann, Miguel A1 - Ross, Matthew A1 - Minitti, Michael P. A1 - Turner, Joshua J. A1 - Moeller, Stefan P. A1 - Schlotter, William F. A1 - Dakovski, Georgi L. A1 - Khalil, Munira A1 - Huse, Nils A1 - Föhlisch, Alexander T1 - Principles of femtosecond X-ray/optical cross-correlation with X-ray induced transient optical reflectivity in solids JF - Applied physics letters N2 - The discovery of ultrafast X-ray induced optical reflectivity changes enabled the development of X-ray/optical cross correlation techniques at X-ray free electron lasers worldwide. We have now linked through experiment and theory the fundamental excitation and relaxation steps with the transient optical properties in finite solid samples. Therefore, we gain a thorough interpretation and an optimized detection scheme of X-ray induced changes to the refractive index and the X-ray/optical cross correlation response. (C) 2015 AIP Publishing LLC. Y1 - 2015 U6 - https://doi.org/10.1063/1.4907949 SN - 0003-6951 SN - 1077-3118 VL - 106 IS - 6 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Eckert, Sebastian A1 - Vaz da Cruz, Vinícius A1 - Ochmann, Miguel A1 - Ahnen, Inga von A1 - Föhlisch, Alexander A1 - Huse, Nils T1 - Breaking the symmetry of pyrimidine BT - solvent effects and core-excited state dynamics JF - The journal of physical chemistry letters N2 - Symmetry and its breaking crucially define the chemical properties of molecules and their functionality. Resonant inelastic X-ray scattering is a local electronic structure probe reporting on molecular symmetry and its dynamical breaking within the femtosecond scattering duration. Here, we study pyrimidine, a system from the C-2v point group, in an aqueous solution environment, using scattering though its 2a(2) resonance. Despite the absence of clean parity selection rules for decay transitions from in-plane orbitals, scattering channels including decay from the 7b(2) and 11a(1) orbitals with nitrogen lone pair character are a direct probe for molecular symmetry. Computed spectra of explicitly solvated molecules sampled from a molecular dynamics simulation are combined with the results of a quantum dynamical description of the X-ray scattering process. We observe dominant signatures of core-excited Jahn-Teller induced symmetry breaking for resonant excitation. Solvent contributions are separable by shortening of the effective scattering duration through excitation energy detuning. Y1 - 2021 U6 - https://doi.org/10.1021/acs.jpclett.1c01865 SN - 1948-7185 VL - 12 IS - 35 SP - 8637 EP - 8643 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Fondell, Mattis A1 - Eckert, Sebastian A1 - Jay, Raphael Martin A1 - Weniger, Christian A1 - Quevedo, Wilson A1 - Niskanen, Johannes A1 - Kennedy, Brian A1 - Sorgenfrei, Florian A1 - Schick, Daniel A1 - Giangrisostomi, Erika A1 - Ovsyannikov, Ruslan A1 - Adamczyk, Katrin A1 - Huse, Nils A1 - Wernet, Philippe A1 - Mitzner, Rolf A1 - Föhlisch, Alexander T1 - Time-resolved soft X-ray absorption spectroscopy in transmission mode on liquids at MHz repetition rates JF - Structural dynamics N2 - We present a setup combining a liquid flatjet sample delivery and a MHz laser system for time-resolved soft X-ray absorption measurements of liquid samples at the high brilliance undulator beamline UE52-SGM at Bessy II yielding unprecedented statistics in this spectral range. We demonstrate that the efficient detection of transient absorption changes in transmission mode enables the identification of photoexcited species in dilute samples. With iron(II)-trisbipyridine in aqueous solution as a benchmark system, we present absorption measurements at various edges in the soft X-ray regime. In combination with the wavelength tunability of the laser system, the set-up opens up opportunities to study the photochemistry of many systems at low concentrations, relevant to materials sciences, chemistry, and biology. (C) 2017 Author(s). Y1 - 2017 U6 - https://doi.org/10.1063/1.4993755 SN - 2329-7778 VL - 4 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Ochmann, Miguel A1 - Vaz da Cruz, Vinicius A1 - Eckert, Sebastian A1 - Huse, Nils A1 - Föhlisch, Alexander T1 - R-Group stabilization in methylated formamides observed by resonant inelastic X-ray scattering JF - Chemical communications: ChemComm N2 - The inherent stability of methylated formamides is traced to a stabilization of the deep-lying sigma-framework by resonant inelastic X-ray scattering at the nitrogen K-edge. Charge transfer from the amide nitrogen to the methyl groups underlie this stabilization mechanism that leaves the aldehyde group essentially unaltered and explains the stability of secondary and tertiary amides. Y1 - 2022 U6 - https://doi.org/10.1039/d2cc00053a SN - 1359-7345 SN - 1364-548X VL - 58 IS - 63 SP - 8834 EP - 8837 PB - The Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Zaitsev-Doyle, John J. A1 - Puchert, Anke A1 - Pfeifer, Yannik A1 - Yan, Hao A1 - Yorke, Briony A. A1 - Müller-Werkmeister, Henrike A1 - Uetrecht, Charlotte A1 - Rehbein, Julia A1 - Huse, Nils A1 - Pearson, Arwen R. A1 - Sans, Marta T1 - Synthesis and characterisation of alpha-carboxynitrobenzyl photocaged l-aspartates for applications in time-resolved structural biology JF - RSC Advances N2 - We report a new synthetic route to a series of a-carboxynitrobenzyl photocaged L-aspartates for application in time-resolved structural biology. The resulting compounds were characterised in terms of UV/Vis absorption properties, aqueous solubility and stability, and photocleavage rates (tau = ms to ms) and quantum yields (phi = 0.05 to 0.14). Y1 - 2019 U6 - https://doi.org/10.1039/c9ra00968j SN - 2046-2069 VL - 9 IS - 15 SP - 8695 EP - 8699 PB - Royal Society of Chemistry CY - Cambridge ER -