Time-Resolved X-Ray. with One Trillion Photons. XDL Workshop tickle and probe, Cornell University, June 21, 2011

Transcription

1 Time-Resolved X-Ray Spectroscopies and Scattering with One Trillion Photons Christian Bressler XDL Workshop tickle and probe, Cornell University, June 21, 2011

2 Dynamic Studies in Photochemistry Ru(bpy) 3 (aq) 1. Intramolecular Charge Transfer Absorption / a.u. 0,5 0,4 03 0,3 0,2 0,1 0, X-Ray XRay Probe Energy / ev 2. Towards Solvation Dynamics Absorption / a.u. 1,0 0,5 0,0 I - I 0 Nascent I 0 (aq) X-Ray Probe Energy (ev) 3. Light-Induced Spin Crossover Fe(bpy) 3 (aq)

3 What are the fundamental timescales? Chemistry and Biochemistry Photosynthesis Vision Molecular Vibrations Protein Folding Strings, Particle Molecular l Rotations ti Cosmology Collisions Electron dynamics harpo yacto zepto atto femto pico nano micro milli Time /seconds

4 Now for the low-lying fruit (K edges) RIXS, X-Ray Raman Valence XES K XES Transm ansmission XAFS Fluorescence XAFS , Aqueous Sample Concentation / mm Incident Photons for S/N = 10

5 Towards Solvation Dynamics -Distinguishg IVR from guest-host interactions -Example: NO/Rg matrix

6 Rydberg NO in rare gas matrices: bubble formation

7 Ultrafast Processes in the Condensed n d Phase (of any kind) Speed of Sound: >10 Å/ps ca Solvent Molecules l involved X-Ray Absorption Spectroscopy X Ray Absorption Spectroscopy Singles Out Reaction Center...

8 Electron Detachment Reactions (via XAFS) 2s 5p Absorption / a.u. 1,0 0,5 0,0 I - I X-Ray Probe Energy (ev) Pham et al., JACS (2007) Nascent I atoms in solution I. Tavernelli (EPFL)

9 EXAFS and XANES of nascent iodine radicals static 300 fs 50 ps 50 ps 300 fs 50 ps V.-T. Pham et al. Chem. Phys. (2010) V.-T. Pham, PhD thesis (2010) V.-T. Pham et al. Submitted (2011) I - I 0

10 Now to something completely different. LS HS 10 C. Consani et al. Angew Chem (2009)

11 Towards Transient Structures via TR-XAFS A / a.u. 0 3 A x 1 1 HS LS 50 ps X-Ray Probe Energy / ev 665 ps (k) x k 2 0 Photoelectron Wavevector k / Å t < t = 50 ps Exp. (Ground State) Fit R Fe-N = 0.2 ±0.008 Å M. Benfatto (INFN Rome) B k 2 (k) x k 70 ps 0 W. Gawelda et al. 11 Phys. Rev. Lett. (2007) Exp. (Transient) Fit Photoelectron Wavevector k / Å -1 W. Gawelda et al. J. Chem. Phys. (2009)

12 ps and fs XANES (Synchrotron) A / a.u u. x 10 3 A HS LS 50 ps 300 fs X-Ray Probe Energy / ev C. Bressler et al., Science (2009)

13 Identifying intermediate states... R Fe-N N =0.2 Å Time Delay / fs 250 fs (instrument response): 140(30) fs hard x-ray pulse 115(10) fs laser pulse <100(30) fs time zero drifts photons/pulse (2 khz, 2 ev BW)

14 Combined optical and x-ray results?? b) 20 fs 1 MLCT 3 MLCT 120 fs <130 fs Energy 1 A 1 (LS) R (Fe-N) 5 T (HS) ps Need now a Spin-Sensitive Sensitive Tool!!

15 Spin sensitivity e 3p 2p IP 1s Courtesy: Pieter Glatzel (ESRF)

16 1s XES of a spin transition molecule exchange (J) 3d n p 1s2p 1s3p 1sVB 1s Fe II 3d 6 S = 0 2 T,p h G. Vankó et al., J. Phys. Chem. B 110 (2006) 11647

17 Towards ultrafast X-ray Emission Spectroscopy ph/pulse (100 ps) ph/pulse (200 fs) 10-3 ph/pulse (100 ps XES) a) b) D1 D2 X L S D3 c) T = 960 ns Ge(440) Laser 0.5 ms G. Vankó et al., Angew. Chem. Int. Ed. (2010)

18 Direct spin probing: first TR-XES (ps) Femtosecond Time Resolution Ideally suited for single wavelength XFEL experiments MHz repetition rates!!!! G. Vanko et al., Angew. Chem. Int. Ed., (2010)

19 MHz Laser Installation at ESRF Ready to Pump-Probe at MHz rep-rates!! 19

20 ID26 X-ray Emission/Absorption Spectroscopy MHz

21 21 ID26/ESRF (March 2011)

22 22 APS, sector 7 (March 2011)

23 Picosecond K alpha XES at APS 1 khz pp studies at SLS (Angew. Chem. 2010) 0.13 MHz at APS 23

24 back to the future: Entering the femtosecond time scale (again) Linac coherent light source (LCLS) Credits: D. Fritz, M. Cammarata (SLAC)

25 XPP Commissioning (LCLS, Oct 2010) (Cammarata)

26 One single File (10 min scan) at LCLS

27 Oct 2010: XPP commissioning XANES / a.u. Tra ansient 0,1 0,0 SLS ( t = 50 ps) SLS ( t = 300 fs) f ) XPP ( t = fs) X-Ray Probe Energy / ev

28 Real-Time Traces sorption X-Ra ay Trans sient Ab 0,003 0,002 0,001 0,000 Science 2009 Fit curve 2009 XPP , Laser-X-RayTimeDelay/fs

29 Transient Spectra around Time Zero 0,036 0,06 Trans sient XANES 0,034 0,032 XANES 0,04 0, Laser X-Ray Time Delay / fs 0,00 Po opulation 1,0 0,9 0,8 0,1 1,3 MLCT 1 GS 5 HS Spin Flip? Tra ansient XAN NES 0,0025 0, , Time / fs X-Ray Probe Energy / ev

30 Looking into the raw data

31 Summary of combined optical/xas studies?? e g t 2g 120 fs a) Energy 1,3 MLCT 1 T 2 1 T 1 3 T 2 1,3 T :<60 fs 5 E 3 T 1 1 A 1 5 T 2 R (Fe-N) Need to include XES (spin) and even XRD (solvent) experiments at APS/ESRF to prepare for LCLS

32 Next Step: Exploit Complementary Structural Tools (LCLS project 2011): Towards understanding chemical reactivity e - XES: occupied DOS (spin) XAS: empty DOS (orbitals) XRD: geometric structures Collaboration: 1) Ru(II) Ru(III) (XAS, XES, optical) 2) IVR + e-transport (XRD, optical) 3) Co(III) Co(II) (XAS, XES, optical) 4) Co(II) LS HS (XAS, XES) M. Nielsen (Copenhagen) V. Sundström dtö (Lund) G. Vanko (Budapest) P. Glatzel (ESRF) A. Meents (Petra3) R. Abela (SwissFEL)

33 Conclusions Towards Solvation Dynamics Absorption / a.u. 1,0 0,5 0,0 I - I 0 Nascent I 0 (aq) X-Ray Probe Energy (ev) - We can follow the sequence of events from 300 fs onwards Even the (few) ps time scale we do not fully understand Theoretical input important - We need to know how things evolve between fs New experiments are planned (theory required) Light-Induced Spin Crossover Fe(bpy) 3 (aq) - We do not understand this correlated SCO behavior! but we are already looking into the elementary steps!!!

34 Acknowledgments 34 University of Copenhagen - Martin Meedom Nielsen - Kristoffer Haldrup Lund University - Villy Sundström - Sophie Canton - Jens Uhlig - Grigory Smolentsev SwissFEL - Rafael labela Argonne National Lab (APS) - Steven Southworth - Anne-Marie March (MHz laser) - Gilles Doumy - Elliot Kanter - Dipanwita Ray - Robert Dunford - Linda Young KFKI Budapest - György Vankó ESRF European XFEL Facility - Pieter Glatzel - Wojciech Gawelda - Erik Gallo - Andreas Galler LCLS (SLAC) K. Gaffney, L. X. Chen, H. Ihee - David Fritz, Marco Cammarata (XPP Oct 2010)