TY  - JOUR
A1  - Eckert, Sebastian
A1  - Niskanen, Johannes
A1  - Jay, Raphael Martin
A1  - Miedema, Piter S.
A1  - Fondell, Mattis
A1  - Kennedy, Brian
A1  - Quevedo, Wilson
A1  - Iannuzzi, Marcella
A1  - Föhlisch, Alexander
T1  - Valence orbitals and local bond dynamics around N atoms of histidine under X-ray irradiation
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - The valence orbitals of aqueous histidine under basic, neutral and acidic conditions and their X-ray induced transformations have been monitored through N 1s resonant inelastic X-ray scattering. Using density functional ab initio molecular dynamics simulations in the core-hole state within the Z + 1 approximation, core-excitation-induced molecular transformations are quantified. Spectroscopic evidence for a highly directional X-ray-induced local N-H dissociation within the scattering duration is presented for acidic histidine. Our report demonstrates a protonation-state and chemical-environment dependent propensity for a molecular dissociation, which is induced by the absorption of high energy photons. This case study indicates that structural deformations in biomolecules under exposure to ionizing radiation, yielding possible alteration or loss of function, is highly dependent on the physiological state of the molecule upon irradiation.
Y1  - 2017
U6  - https://doi.org/10.1039/c7cp05713j
SN  - 1463-9076
SN  - 1463-9084
VL  - 19
SP  - 32091
EP  - 32098
PB  - Royal Society of Chemistry
CY  - Cambridge
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, Nomi
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  -