Femtosecond Spectroscopy and X-ray Spectroscopy Group

The basic scientific activity of the Femtosecond Spectroscopy and X-ray Spectroscopy Group has been applying spectroscopy techniques based on synchrotron radiation, aiming to study electronic bistability and metastable excited states in transition metal compounds, as well as the electronic structure of oxides with correlated electrons. We have been also working on applying X-ray spectroscopy as probes to study ultrafast structural and electronic dynamics in pump-probe experiments, with ps and fs resolution.

Recently we have started a new activity by realizing a femtosecond transient optical absorption setup in the HELIOS lab of the Wigner RCP. The research opportunities offered by this facility efficiently complements our X-ray and theory programme to tackle ultrafast dynamics of moecular systems in the condensed phase.

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Staff

Students
Szabó, András         M.Sc. in Physics (2012)
Herczeg, Viktória    B.Sc. in Physics (2014)
Kapás, Fanni           M.Sc. in Chemical engineering (2017)

Former members
Bordage, Amélie     Post-doctoral fellow (Feb. 2011- Dec. 2012)
Raiola, Francesco    Post-doctoral fellow (Nov. 2012 - July 2013)
Rozipál, Gábor        Research assistant (Sept. 2012 - Apr. 2013)
Rozsályi, Emese      Post-doctoral fellow (Sep. 2013 - Aug. 2016)
Sas, Norbert           PhD student (2009-2012)
Szabó, András         Research Assistant (2012 - Aug. 2014)

The most relevant part of our research is done at synchrotron radiation facilities and X-ray free electron lasers. Current research topics include studying transition metal oxides with correlated electrons, switchable metal complexes, and ultrafast transitions applying X-ray spectroscopy.

Our group shares a Mössbauer spectroscopy laboratory with the Functional Nanostructures Group. This laboratory is equipped with several spectrometers, of which we mostly use the ones dedicated to emission Mössbauer spectroscopy studies (MES). We run a chemistry laboratory and two isotope laboratories. We have access to other facilities on the KFKI campus through several collaborations with other groups.

FUNDING

A substantial part of our research is supported by the European Research Council under contract StG-259709.

Our study of transition metal oxides are partly supported by the Hungarian Scientific Research Fund (OTKA) under contract No. K 72597.

Based on funding from the HAS (Lendület (Momentum) programme and a grant to improve the infrastructure), we start up a new activity to realize a femtosecond transient optical absorption setup in the HELIOS lab of the Wigner RCP, in collaboration with the group of Péter Dombi. The research opportunities offered by such a facility shall efficiently complement our X-ray and theory programme.

HIGHLIGHTS


Insights into the function of a light-harvesting model system
Ultrafast photoinduced electron transfer preceding energy equilibration still poses many experimental and conceptual challenges to the optimization of photoconversion since an atomic-scale description has so far been beyond reach. Here we combine femtosecond transient optical absorption spectroscopy with ultrafast X-ray emission spectroscopy and diffuse X-ray scattering at the SACLA facility to track the non-equilibrated electronic and structural dynamics within a bimetallic donor–acceptor complex that contains an optically dark centre. Exploiting the 100-fold increase in temporal resolution as compared with storage ring facilities, these measurements constitute the first X-ray-based visualization of a non-equilibrated intramolecular electron transfer process over large interatomic distances. Experimental and theoretical results establish that mediation through electronically excited molecular states is a key mechanistic feature. The present study demonstrates the extensive potential of femtosecond X-ray techniques as diagnostics of non-adiabatic electron transfer processes in synthetic and biological systems, and some directions for future studies, are outlined.
Read paper "Visualizing the non-equilibrium dynamics of photoinduced intramolecular electron transfer with femtosecond X-ray pulses" at Nature Communications,
or the press release by our colleagues at Lund University


Tracking excited-state charge and spin dynamics in iron coordination complexes
Photo-induced spin-state transition of molecular compounds of iron has great potential for applications in molecular devices. The low to high spin excitation in Fe(II) compounds involves flipping two electron spins in less than 300 femtosecond. Therefore, the detailed mechanism of the ultrafast spin switching has been ill-understood due to the lack of proper tools to provide insights in the ultrashort time window. We have managed to close this knowledge gap exploiting the spin momentum sensitivity of X-ray emission spectroscopy at the Linac Coherent Light Source, the first hard X-ray free electron laser (at the Stanford Linear Accelerator Center, USA), in a pioneering experiment using 100 femtosecond time resolution. We were able to determine the de-excitation sequence for a benchmark Fe(II) molecule showing a singlet to quintet transition, establishing the critical role of intermediate triplet spin states in the transition mechanism.
Read paper "Tracking excited-state charge and spin dynamics in iron coordination complexes" at Nature


On the microscopic origin of the nanoscale magnetic-electronic phase separation in LSCO
Investigating the roots of a nanoscale magneto-electronic phase separation (responsible for their magnetoresistance as well as cooperative electric and magnetic phase transitions) in bulk Sr-doped LaCoO3 (LSCO), we have combined local spectroscopic techniques as synchrotron XES and laboratory Mössbauer spectroscopy to identify and characterize the clusterization process. A simple model based on the random distribution of the doping Sr ions describes well both the doping-driven evolution of the separated phases and the variation of the Co spin state.
Read paper "Microscopic origin of the nanoscale magnetic-electronic phase separation in LSCO" at Phys. Rev. B 88 (2013) 035125 by Z. Németh et al.

Read some more highlights here

RECENT PAPERS

March, A. M.; Assefa, T. A.; Boemer, C.; Bressler, C.; Britz, A.; Diez, M.; Doumy, G.; Galler, A.; Harder, M.; Khakhulin, D.; Németh, Z.; Pápai, M; Schulz, S.; Southworth, S. H.; Yavas, H.; Young, L.; Gawelda, W. & Vankó, G.
Probing Transient Valence Orbital Changes with Picosecond Valence-to-Core X-ray Emission Spectroscopy
J. Phys. Chem. C 121 (2017) 2620–2626.

Z. Németh, J. Szlachetko, É. G. Bajnóczi, G. Vankó
Laboratory von Hámos X-ray Spectroscopy for Routine Sample Characterization
Review of Scientific Instruments 87 (2016) 103105, arXiv:1607.08045

Biasin, E.; van Driel, T. B.; Kjær, K. S.; Dohn, A. O.; Christensen, M.; Harlang, T.; Chabera, P.; Liu, Y.; Uhlig, J.; Pápai, M.; Németh, Z.; Hartsock, R.; Liang, W.; Zhang, J.; Alonso-Mori, R.; Chollet, M.; Glownia, J. M.; Nelson, S.; Sokaras, D.; Assefa, T. A.; Britz, A.; Galler, A.; Gawelda, W.; Bressler, C.; Gaffney, K. J.; Lemke, H. T.; Møller, K. B.; Nielsen, M. M.; Sundström, V.; Vankó, G.; Wärnmark, K.; Canton, S. E. & Haldrup, K.
Femtosecond X-Ray Scattering Study of Ultrafast Photoinduced Structural Dynamics in Solvated [Co(terpy)2]2+
Phys. Rev. Lett. 117 013002 (2016), available also at arxiv.com arXiv:1607.01511

M. Pápai, G. Vankó, T. Rozgonyi, T. Penfold
High Efficiency Iron Photosensitiser Explained with Quantum Wavepacket Dynamics
J. Phys. Chem. Lett. 7 (2016) 2009

T. J. Penfold, M. Pápai, T. Rozgonyi, K. B. Møller, G. Vankó
Probing Spin-Vibronic Dynamics Using Femtosecond X-ray Spectroscopy
Faraday Discussions 2016, DOI: 10.1039/C6FD00070C

Haldrup, K.; Gawelda, W.; Abela, R.; Alonso-Mori, R.; Bergmann, U.; Bordage, A.; Cammarata, M.; Canton, S. E.; Dohn, A. O.; van Driel, T. B.; Fritz, D. M.; Galler, A.; Glatzel, P.; Harlang, T.; Kjær, K. S.; Lemke, H. T.; Møller, K. B.; Németh, Z.; Pápai, M.; Sas, N.; Uhlig, J.; Zhu, D.; Vankó, G.; Sundström, V.; Nielsen, M. M., and Bressler, C.
Observing Solvation Dynamics with Simultaneous Femtosecond X-ray Emission Spectroscopy and X-ray Scattering
J. Phys. Chem. B 120 (2016) 1158–1168

S.E. Canton, K.S. Kjær, G. Vankó, T. B. van Driel, S. Adachi, A. Bordage, C. Bressler, P. Chabera, M. Christensen, A.O. Dohn, A. Galler, W. Gawelda, D. Gosztola, K. Haldrup, T. Harlang, Y. Liu, K. B. Møller, Z. Németh, S. Nozawa, M. Pápai, T. Sato, T. Sato, K. Suarez-Alcantara, T. Togashi, K. Tono, J. Uhlig, D. A. Vithanage, K. Wärnmark, M. Yabashi, J. Zhang, V. Sundström and M. M. Nielsen
Visualizing the Nonequilibrium Dynamics of Photoinduced Intramolecular Electron Transfer with Femtosecond X-ray Pulses
Nature Communications 6 (2015) 6359

G. Vankó, A. Bordage, M. Pápai, K. Haldrup, P. Glatzel, A. M. March, G. Doumy, A. Britz, A. Galler, T. Assefa, D. Cabaret, A. Juhin, T. B. van Driel, K. S. Kjær, A. Dohn, K B. Møller, H. T. Lemke, E. Gallo, M. Rovezzi, Z. Németh, E. Rozsályi, T. Rozgonyi, J. Uhlig, V. Sundström, M. M. Nielsen, L. Young, S. H. Southworth, C. Bressler, and W. Gawelda
Detailed Characterization of a Nanosecond-Lived Excited State: X-Ray and Theoretical Investigation of the Quintet State in Photoexcited [Fe(terpy)2]2+
J. Phys. Chem. C 119 (2015) 5888-5902

March, A. M.; Assefa, T. A.; Bressler, C.; Doumy, G.; Galler, A.; Gawelda, W.; Kanter, E. P.; Németh, Z.; Pápai, M.; Southworth, S. H.; Young, L. & Vankó, G.
Feasibility of Valence-to-Core X-ray Emission Spectroscopy for Tracking Transient Species
J. Phys. Chem. C 119 (2015) 14571-14578

Zhang, W.; Alonso-Mori, R.; Bergmann, U.; Bressler, C.; Chollet, M.; Galler, A.; Gawelda, W.; Hadt, R. G.; Hartsock, R. W.; Kroll, T.; Kjaer, K. S.; Kubicek, K.; Lemke, H. T.; Liang, H. W.; Meyer, D. A.; Nielsen, M. M.; Purser, C.; Robinson, J. S.; Solomon, E. I.; Sun, Z.; Sokaras, D.; van Driel, T. B.; Vankó, G.; Weng, T.-C.; Zhu, D. & Gaffney, K. J.
Tracking excited-state charge and spin dynamics in iron coordination complexes
Nature 509 (2014) 345-348

Fredin, L. A.; Pápai, M.; Rozsályi, E.; Vankó, G.; Wärnmark, K.; Sundström, V.; Persson, P.
Exceptional Excited-State Lifetime of an Iron(II)−N‑Heterocyclic Carbene Complex Explained
J. Phys. Chem. Lett. 4 (2014) 2066–2071.

Szilágyi, E.; Kótai, E.; Rata, D.; Németh, Z., Vankó, G.
Channelling study of La1−xSrxCoO3 films on different substrates
NIM B 332 (2014) 393 - 396

C. Bressler, W. Gawelda, A. Galler, M. M. Nielsen, K. Haldrup, V. Sundström, G. Doumy, A. M. March, S. H. Southworth, L. Young, G. Vankó
Ultrafast Electronic and Structural Intramolecular Dynamics and Guest-host interactions observed via simultaneous X-ray spectroscopies and diffuse scattering
Faraday Discussions 171 (2014) 169–178.

Kuzmann, E.; Zoppellaro, G.; Pechousek, J.; Cuda, J.; Klencsár, Z.; Hommonay, Z.; Tucek, J.; Szalay, R.; Pápai, M.; Machala, L.; Zboril, R.
Ferromagnetic Coupling in an Fe[C(SiMe3)3]2/Ferrihydrite Hetero-Mixture Molecular Magnet
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY (2014) 3178-3183.

M. Pápai, G. Vankó
On Predicting Mössbauer Parameters of Iron-Containing Molecules with Density-Functional Theory
J. Chem. Theory Comput. 9 (2013), pp 5004–5020
(See the highlight by the Mössbauer Effect Data Center )

Pápai M, Vankó G, de Graaf C, Rozgonyi T
Theoretical investigation of the electronic structure of Fe(II) complexes at spin-state transitions
JOURNAL OF CHEMICAL THEORY AND COMPUTATION 9 (2013) 509-519.

Z. Németh, A. Szabó, K. Knizek, M. Sikora, R. Chernikov, N. Sas, C. Bogdán, D. L. Nagy, G. Vankó
On the microscopic origin of the magneto-electronic phase separation in Sr-doped LaCoO3
Phys. Rev. B 88 (2013) 035125. arxiv preprint

Vankó G, Bordage A, Glatzel P, Gallo E, Rovezzi M, Gawelda W, Galler A, Bressler C, Doumy G, March AM, Kanter EP, Young L, Southworth SH, Canton SE, Uhlig J, Smolentsev G, Sundström V, Haldrup K, van Driel TB, Nielsen MM, Kjaer KS, Lemke HT
Spin-state studies with XES and RIXS: From static to ultrafast
JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 188 (2013) 166--171.
(Invited paper for the special issue: "Progress in RIXS")
Ranked among the top 25 most downloaded articles of the journal as:
6th between January to December, 2013 (full year)
12th between October to December, 2012

A. Bordage, M. Pápai, N. Sas, J. Szlachetko, M. Nachtegaal, G. Vankó
On the sensitivity of hard X-ray spectroscopies to the chemical state of Br
PHYS. CHEM. CHEM. PHYS. 15 (2013) 11088–11098

Canton, S. E.; Zhang, X.; Zhang, J.; van Driel, T. B.; Kjær, K. S.; Haldrup, K.; Chabera, P.; Harlang, T.; Suarez-Alcantara, K.; Liu, Y.; Pérez, J.; Bordage, A.; Pápai, M.; Vankó, G.; Jennings, G.; Kurtz, C. A.; Rovezzi, M.; Glatzel, P.; Smolentsev, G.; Uhlig, J.; Dohn, A. O.; Christensen, M.; Galler, A.; Gawelda, W.; Bressler, C.; Lemke, H. T.; Møller, K. B.; Nielsen, M. M.; Lomoth, R.; Wärnmark, K., Sundström, V.
Toward Highlighting the Ultrafast Electron Transfer Dynamics at the Optically Dark Sites of Photocatalysts
J. PHYS. CHEM. LETTERS 4 (2013) 1972–1976.

R. Kurian, M.M. van Schooneveld, Z. Németh, G. Vankó, F.M.F. de Groot:
Temperature-Dependent 1s2p Resonant Inelastic X-ray Scattering of CoO
J. Phys. Chem. C 117 (2013) 2976 - 2981.

Renz F, Vankó G, Homenya P, Saadat R, Németh Z, Huotari S
Hard-X-ray-induced thermal hysteresis (HAXITH) in a molecular switchable solid
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY (16) pp. 2653-2655. (2012)

Haldrup K, Vankó G, Gawelda W, Galler A, Doumy G, March AM, Kanter EP, Bordage A, Dohn A, van Driel TB, Kjaer KS, Lemke HT, Canton SE, Uhlig J, Sundstrom V, Young L, Southworth SH, Nielsen MM, Bressler C
Guest-Host Interactions Investigated by Time-Resolved X-ray Spectroscopies and Scattering at MHz Rates: Solvation Dynamics and Photoinduced Spin Transition in Aqueous Fe(bipy)(3)(2+)
JOURNAL OF PHYSICAL CHEMISTRY A 116 (2012) 9878-9887.
(highlighted by APS:)

Deák L, Bottyán L, Fülöp T, Kertész G, Nagy DL, Ruffer R, Spiering H, Tanczikó F, Vankó G
Switching Reciprocity On and Off in a Magneto-Optical X-Ray Scattering Experiment Using Nuclear Resonance of alpha-Fe-57 Foils
PHYSICAL REVIEW LETTERS 109:(23) Paper 237402. 4 p. (2012)
(This work has been highlighted as an ESRF Spotlight )

Loa I, Syassen K, Monaco G, Vankó G, Krisch M, Hanfland M
Plasmons in Sodium under Pressure: Increasing Departure from Nearly Free-Electron Behavior
PHYSICAL REVIEW LETTERS 107:(8) Paper 086402. (2011)

Vankó G, Glatzel P, Pham VT, Abela R, Grolimund D, Borca CN, Johnson SL, Milne CJ, Bressler C
Picosecond Time-Resolved X-Ray Emission Spectroscopy: Ultrafast Spin-State Determination in an Iron Complex
ANGEWANDTE CHEMIE INTERNATIONAL EDITION 49:(34) pp. 5910-5912. (2010)

EXPERIMENTS
Oct 2017, ELI Beamlines, Dolní Břežany, Czech Republic
Sep 2017, European XFEL, Hamburg, Germany
June 2017, SACLA, Japan
Dec 2016, 7-ID, APS, Argonne, USA
Sep 2016, P01, Petra III., Hamburg, Germany
Apr 2016, 7-ID, APS, Argonne, USA
Feb 2016, 7-ID, APS, Argonne, USA
Nov 2015, SACLA, Japan
Oct 2015, SuperXAS, Swiss Light Source
Aug. 2015, XPP, LCLS, Stanford, USA
June 2015, ID09, ESRF, Grenoble, France
May 2015, SACLA, Japan
March 2015, 7-ID, APS, Argonne, USA
Feb. 2015, ID26, ESRF, Grenoble, France
Oct. 2014, SuperXAS, Swiss Light Source
July 2014, 7-ID, APS, Argonne, USA

June 2014, SACLA, Japan

May 2014, ID09, ESRF, Grenoble, France
Feb. 2014, XPP, LCLS, Stanford, USA
Nov 2013, 7-ID, APS, Argonne, USA
May 2013, ID09, ESRF, Grenoble, France
Apr. 2013, BM24, ESRF, Grenoble, France
Jan. 2013, XPP, LCLS, Stanford, USA

PRESENTATIONS

  • G. Vankó: Resonant and Non-resonant Hard X-ray Emission Spectroscopy Go Dynamic (invited)

    and Z. Németh: X-ray Spectroscopy Studies of Light-excited States Trapped in Solids (invited)

    Symposium “Ultrafast experiments at XFEL sources, the first 5 years and beyond”, 25-27 August, 2014, Denmark

  • G. Vankó: Molecular colour movies: the use of hard X-ray spectroscopy in ultrafast experiments (invited)
    SwissFEL ESA Experimental Techniques Symposium, May 28, Paul Scherrer Institut, Villigen, Switzerland

  • In the media/news (Sajtó- és médiamegjelenések)

    • 2017. október 9. MTA WIGNER FK HÍREI: Kipróbáltuk az európai röntgenlézert
    • 2015. március 6. Úttörő lépés a fényhasznosító molekulák működésének megértése felé
    • 2014. május 5. mta.hu: Lendületes kutatók átalakulás közben figyelték meg a molekulákat
    • 2013. szeptember 19. mta.hu: A megkezdett kísérletek folytatását és új, hazai kísérleti bázis építését teszi lehetővé a Lendület
    • 2010. november 12. Interjú Vankó Györggyel, az ERC Starting Grant egyik nyertesével kutatási terveiről és kutatásainak várható hatásairól az Inforádió november 12-i "Géniusz" nevű tudományos magazinjában. 1. rész, 2. rész