@article{EckertBeyePietzschetal.2015, author = {Eckert, Sebastian and Beye, Martin and Pietzsch, Annette and Quevedo, Wilson and Hantschmann, Markus and Ochmann, Miguel and Ross, Matthew and Minitti, Michael P. and Turner, Joshua J. and Moeller, Stefan P. and Schlotter, William F. and Dakovski, Georgi L. and Khalil, Munira and Huse, Nils and F{\"o}hlisch, Alexander}, title = {Principles of femtosecond X-ray/optical cross-correlation with X-ray induced transient optical reflectivity in solids}, series = {Applied physics letters}, volume = {106}, journal = {Applied physics letters}, number = {6}, publisher = {American Institute of Physics}, address = {Melville}, issn = {0003-6951}, doi = {10.1063/1.4907949}, pages = {4}, year = {2015}, abstract = {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.}, language = {en} } @article{FondellEckertJayetal.2017, author = {Fondell, Mattis and Eckert, Sebastian and Jay, Raphael Martin and Weniger, Christian and Quevedo, Wilson and Niskanen, Johannes and Kennedy, Brian and Sorgenfrei, Florian and Schick, Daniel and Giangrisostomi, Erika and Ovsyannikov, Ruslan and Adamczyk, Katrin and Huse, Nils and Wernet, Philippe and Mitzner, Rolf and F{\"o}hlisch, Alexander}, title = {Time-resolved soft X-ray absorption spectroscopy in transmission mode on liquids at MHz repetition rates}, series = {Structural dynamics}, volume = {4}, journal = {Structural dynamics}, publisher = {American Institute of Physics}, address = {Melville}, issn = {2329-7778}, doi = {10.1063/1.4993755}, pages = {11}, year = {2017}, abstract = {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).}, language = {en} } @article{ZaitsevDoylePuchertPfeiferetal.2019, author = {Zaitsev-Doyle, John J. and Puchert, Anke and Pfeifer, Yannik and Yan, Hao and Yorke, Briony A. and M{\"u}ller-Werkmeister, Henrike and Uetrecht, Charlotte and Rehbein, Julia and Huse, Nils and Pearson, Arwen R. and Sans, Marta}, title = {Synthesis and characterisation of alpha-carboxynitrobenzyl photocaged l-aspartates for applications in time-resolved structural biology}, series = {RSC Advances}, volume = {9}, journal = {RSC Advances}, number = {15}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2046-2069}, doi = {10.1039/c9ra00968j}, pages = {8695 -- 8699}, year = {2019}, abstract = {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).}, language = {en} } @article{EckertVazdaCruzOchmannetal.2021, author = {Eckert, Sebastian and Vaz da Cruz, Vin{\´i}cius and Ochmann, Miguel and Ahnen, Inga von and F{\"o}hlisch, Alexander and Huse, Nils}, title = {Breaking the symmetry of pyrimidine}, series = {The journal of physical chemistry letters}, volume = {12}, journal = {The journal of physical chemistry letters}, number = {35}, publisher = {American Chemical Society}, address = {Washington}, issn = {1948-7185}, doi = {10.1021/acs.jpclett.1c01865}, pages = {8637 -- 8643}, year = {2021}, abstract = {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.}, language = {en} } @article{OchmannVazdaCruzEckertetal.2022, author = {Ochmann, Miguel and Vaz da Cruz, Vinicius and Eckert, Sebastian and Huse, Nils and F{\"o}hlisch, Alexander}, title = {R-Group stabilization in methylated formamides observed by resonant inelastic X-ray scattering}, series = {Chemical communications: ChemComm}, volume = {58}, journal = {Chemical communications: ChemComm}, number = {63}, publisher = {The Royal Society of Chemistry}, address = {Cambridge}, issn = {1359-7345}, doi = {10.1039/d2cc00053a}, pages = {8834 -- 8837}, year = {2022}, abstract = {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.}, language = {en} }