Autor: Chergui, Majed - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Ultrafast energy transfer from photoexcited tryptophan to the haem in cytochrome c
Autorzy:: Menzi, Samuel
Cirelli, Claudio
Ingle, Rebecca A.
Lima, Frederico A.
Pamfilidis, Georgios
Milne, Christopher J.
Knopp, Gregor
Rodriguez-Fernandez, Angel
Rouxel, Jérémy
Kinschel, Dominik
Gawelda, Wojciech
Kubicek, Katharina
Arrell, Christopfer A.
Khakhulin, Dmitry
Johnson, Philip J. M.
Chergui, Majed
Szlachetko, Jakub
Bressler, Christian
Biednov, Mykola
Bacellar, Camila
Cannelli, Oliviero
Mancini, Giulia F.
Zhao, Yang
Ozerov, Dmitry
Opis:: We report femtosecond Fe K-edge absorption (XAS) and nonresonant X-ray emission (XES) spectra of ferric cytochrome C (Cyt c) upon excitation of the haem (>300nm) or mixed excitation of the haem and tryptophan (<300 nm). The XAS and XES transients obtained in both excitation energy ranges show no evidence for electron transfer processes between photoexcited tryptophan (Trp) and the haem, but rather an ultrafast energy transfer, in agreement with previous ultrafast optical fluorescence and transient absorption studies. The reported (J. Phys. Chem. B 2011, 115 (46), 13723−13730) decay times of Trp fluorescence in ferrous (∼350 fs) and ferric (∼700 fs) Cyt c are among the shortest ever reported for Trp in a protein. The observed time scales cannot be rationalized in terms of Förster or Dexter energy transfer mechanisms and call for a more thorough theoretical investigation.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Artykuł

na półce

Skocz do pozycji: 2.

Tytuł:: Disentangling the evolution of electrons and holes in photoexcited ZnO nanoparticles
Autorzy:: Gawelda, Wojciech
Katayama, Tetsuo
Ueda, Kiyoshi
March, Anne Marie
Iablonskyi, Denis
Nielsen, Martin M.
Mucke, Melanie
Milne, Christofer
Sala, Leonardo
Pajek, Marek
Yabashi, Maina
Nagornova, Natalia
Szlachetko, Jakub
van Driel, Tim B.
Pope, Thomas
Lehmann, C. Stefan
Doumy, Giles
Motomura, Koji
Ebner, Simon
Penfold, Thomas J.
Chergui, Majed
Knopp, Gregor
Chen, Hui-Yuan
Rossi, Thomas
Southworth, Stephen H.
Togashi, Tadashi
Kumagai, Yoshiaki
Owada, Shigeki
Britz, Alexander
Abela, Rafael
Opis:: The evolution of charge carriers in photoexcited room temperature ZnO nanoparticles in solution is investigated using ultrafast ultraviolet photoluminescence spectroscopy, ultrafast Zn K-edge absorption spectroscopy, and ab initio molecular dynamics (MD) simulations. The photoluminescence is excited at 4.66 eV, well above the band edge, and shows that electron cooling in the conduction band and exciton formation occur in <500 fs, in excellent agreement with theoretical predictions. The x-ray absorption measurements, obtained upon excitation close to the band edge at 3.49 eV, are sensitive to the migration and trapping of holes. They reveal that the 2 ps transient largely reproduces the previously reported transient obtained at 100 ps time delay in synchrotron studies. In addition, the x-ray absorption signal is found to rise in ∼1.4 ps, which we attribute to the diffusion of holes through the lattice prior to their trapping at singly charged oxygen vacancies. Indeed, the MD simulations show that impulsive trapping of holes induces an ultrafast expansion of the cage of Zn atoms in <200 fs, followed by an oscillatory response at a frequency of ∼100 cm−1, which corresponds to a phonon mode of the system involving the Zn sub-lattice.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Artykuł

na półce

Skocz do pozycji: 3.

Tytuł:: Protocols for x-ray transient grating pump/optical probe experiments at x-ray free electron lasers
Autorzy:: Lima, Frederico
Feurer, Thomas
Biednov, Mykola
Zalden, Peter
Serrat, Carles
Dhanalakshmi-Veeraraj, Mano R
Mincigrucci, Riccardo
Staub, Urs
Madsen, Anders
Vila-Comamala, Joan
Knoll, Martin
Bañares, Luis
Cucini, Riccardo
Chergui, Majed
Torre, Renato
Paltanin, Ettore
Ardana-Lamas, Fernando
Frankenberger, Paul
Heder, Siti
Khatu, Nupur N
Rossi, Giorgio
Masciovecchio, Claudio
Szlachetko, Jakub
Gessini, Alessandro
Ferrari, Eugenio
Maznev, Alexei A
Cannizzo, Andrea
Nelson, Keith A
Carrara, Pietro
Milne, Christopher
Berndt, Nadia
Bonetti, Stefano
Beye, Martin
Huang, Xinchao
Bencivenga, Filippo
Fainozzi, Danny
Brioschi, Marta
David, Christian
Mamyrbayev, Talgat
Scholz, Markus
Xu, Han
Gawelda, Wojciech M
Bargheer, Matias
Svetina, Cristian
Engel, Robin Y.
Opis:: Transient grating spectroscopy is a specialized application of the four-wave-mixing methodology and constitutes a versatile technique for investigating the dynamics of vibrational, magnetic and electronic degrees of freedom of matter in a background-free fashion. Recent developments in free-electron laser sources have enabled the extension of this technique into the extreme ultraviolet range. Ongoing efforts to expand transient grating spectroscopy into the x-ray regime promise numerous advantages: (1) substantial penetration depths that allow for probing bulk material properties, (2) element specificity via specific core-excited states, and (3) short wavelengths that allow for excitation gratings with higher momentum transfer and improved spatial resolution. In this study, we comprehensively outline the procedures for conducting x-ray transient grating pump/optical probe experiment. The process encompasses the design and alignment of the experimental setup, as well as the subsequent steps involved in data acquisition and analysis. This paper is intended as a comprehensive guide for researchers interested in implementing x-ray transient grating spectroscopy, providing valuable insights into the intricacies of the experimental workflow required for this novel technique. Furthermore, we discuss the potential for extending this methodology to an x-ray pump/x-ray probe scheme, envisioning a future direction that holds promise for enhancing the capabilities and scope of x-ray transient grating spectroscopy, opening new opportunities for studying ultrafast processes with unprecedented temporal and spatial resolutions.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Artykuł

na półce

Informacja

Wyszukujesz frazę "Chergui, Majed" wg kryterium: Autor