Ultrafast photochemistry and photophysics at FXE …Ultrafast photochemistry and photophysics at...

Ultrafast photochemistry and photophysics at FXE by femtosecond spectroscopy and scattering

Dmitry Khakhulin FXE group, European XFEL

Ultrafast photochemistry and photophysics at FXE, 07.05.2020 Dmitry Khakhulin, FXE group, European XFEL

Hard x-rays (3 – 25 keV) SASE 1 & SASE2 (Coherent) diffraction (Coherent) imaging X-ray spectroscopy

Soft x-rays (0.26 – 3 keV) SASE 3 Coherent imaging Particle & X-ray spectroscopy

XFEL photon beamlines and instruments


Tracking ultrafast coupled electron and structural dynamics induced by light

2. Fs X-ray pulse takes a snapshot

1. Fs laser pulse triggers an ultrafast process


Tracking ultrafast coupled electron and structural dynamics induced by light

[Fe(bpy)3]2+ (bpy = bipyridine)

W. Gawelda, et al., PRL 98 (2007)

C. Bressler, et al., Science 323 (2009)

W. Zhang, et al., Nature 509 (2014)

H.T. Lemke, et al., Nature Comm. 8 (2017)

K. S. Kjær, et al., Chemical Science 10 (2019)

….

Spin state changes

Charge transfer states

Molecular structure and solvation changes

MC states

2. Fs X-ray pulse takes a snapshot

1. Fs laser pulse triggers an ultrafast process


FXE: Towards a High-Speed femtosecond Molecular Camera

LPD

Johann spectrometer

Robot arm

Von Hamos spectrometer

Sample mounting stage (10 axis)

Fine sample stage (3 axis)

Flexible liquid sample support

A Suite of Simultaneous X-Ray Tools :

Single-shot dispersive non-resonant XES: von Hamos

Wide(Small)-angle X-ray Scattering and X-ray Diffraction: LPD and Jungfrau X-ray absorption spectroscopy (5-20 keV): scanning (Si(111) 4-bounce mono)

and single-shot (Spectrum analyzer)

Scanning non-resonant and resonant XES (RXES): Johann spectrometer

“Scientific instrument Femtosecond X-ray Experiments (FXE): instrumentation and baseline experimental capabilities” A. Galler et al., J. Synch. Rad., 26, 1432 (2019)

WAXS/XRD

XES

Diode

XFEL beam

Optical laser beam

XAS ∆t


1. Femtosecond X-ray absorption spectroscopy

Multiple scattering + bound-bound

transitions XANES

Constructive + destructive interference

J. K. Kowalska, et al., Isr. J. Chem., 803, 56, (2016)


1. Femtosecond X-ray absorption spectroscopy

Multiple scattering + bound-bound

transitions XANES

Constructive + destructive interference

H.T. Lemke et al., Nature Comm. 8 (2017)

[Fe(bpy)3]2+ (bpy = bipyridine)



Scanning X-ray absorption spectroscopy at FXE: 4-bounce mono, under commissioning

Iron foil scan: FXE vs literature data

100 eV

fixed undulator gap

[Fe(terpy)2]2+ solution

XANES (TFY/HERFD)

and

EXAFS opportunities

A. Britz et al., Phys. Chem. Chem. Phys. (2020)


Single-shot dispersive X-ray absorption spectroscopy Single-shot measurements require 2 Spectrum Analyzers (SA) Pink beam would provide up to 1% bandwidth (Entire XANES spectrum @ time delay) /shot Self-normalization! Requires a fast readout gated 1D detector (Gotthard)

Y. Obara et al., Optics Express 22 (2014)

SpA-0

SpA-1

C

D. Zhu et al., APL 101 (2012)


Single-shot dispersive X-ray absorption spectroscopy

SpA-0

SpA-1

C

Single-shots @564 kHz detector (Gotthard) frame rate 10 trains, 30 pulses each

D. Zhu et al., APL 101 (2012)

Single-shot measurements require 2 Spectrum Analyzers (SA) Pink beam would provide up to 1% bandwidth (Entire XANES spectrum @ time delay) /shot Self-normalization! Requires a fast readout gated 1D detector (Gotthard)


Potential for 2D spectroscopy using stochastic X-ray pulses

Y. Kayser et al., Nat. Comm., 4761, 10, (2019)

SpA-0

SpA-1

C

RXES map

Von Hamos XES

Johann XES


2. Femtosecond X-ray emission spectroscopy

W. Zhang et al., Nature, 509 (2014) 345

Kβ emission on [Fe(bpy)3]2+


XAS XES


2. Femtosecond X-ray emission spectroscopy

Pump-probe Valence-to-core XES

A.M. March et al., J. Phys. Chem. B, (2017)


Kβ emission on [Fe(bpy)3]2+


XAS XES

[Fe(terpy)2]2+

Probing valence orbitals: similar to valence band XPS, but 1) element-specific 2) no UHV requirement 3) bulk sensitive


Femtosecond X-ray emission spectroscopy at FXE

Ambient conditions (or He atm.) offering 10 degrees of freedom, including 2 independent rotations for Johann and von Hamos spectrometers: x – translation perpendicular to x-ray beam Lower 2-theta rotation (Johann) Upper 2-theta rotation (von Hamos) Lower vertical (y) translation Theta rotation Phi and Chi rotations x, z crossed translations Upper vertical (y) translation

Johann von Hamos


Von Hamos XES at FXE: simultaneous single-shot detection of multiple emission lines

8 x Si(531) 8 x Ge(110)

~ 77 mm

Jungfrau detector

Fe Kα Fe Kβ

Fe Kβ spectra before overlapping

Fe Kβ spectrum

Kβ

Kα

16-crystal spectrometer


Simultaneous Ni Kα (2p 1s), Kβ (3p 1s) and VtC (valence orbitals 1s) XES! Note the intensity differs by 3 orders of magnitude.

Sample: Ni foil Beam: 9.3 keV 830 μJ/ pulse 200 pulses / train Only 10 min of data collection

Von Hamos XES at FXE: simultaneous single-shot detection of multiple emission lines 16-crystal spectrometer


blue: FXE (in the Rowland circle) black: data from DELTA synchrotron

Scanning-type Johann XES at FXE: 5-crystal spectrometer One crystal spectra from FXE

Co Kβ1,3 mainline

Co Kβ1,3 mainline

Co Kβ2,5 Valence-to-core

P. Glatzel et al., Sync. Rad. News, 12 (2009)


3. Differential solution scattering – decorrelating the solute and the solvent observables

∆S (Q, t) = ∆Ssolute(Q, t) + ∆Scage(Q, t) +

∆⋅

∂∂

+∆⋅∂

∂ )()()()( tQStTT

QS solvsolv ρρ

solvent

ESRF – 25.2 keV High resolution scattering

Aqueous [Fe(bpy)3]2+

D. Khakhulin et al. Phys. Chem. Chem. Phys., 21, 9277 (2019)


Direct structural sensitivity to the solute and the solvation Aqueous [Fe(bpy)3]2+

Transient Solute structure (100 ps) Solvation structure (100 ps)

TRWAXS at 25.2 keV with ML mono (ID09, ESRF) AIMD by L. M. Lawson Daku L. M. Lawson Daku, PCCP, (2018)

D. Khakhulin et al. Phys. Chem. Chem. Phys., 21, 9277 (2019)


Further examples for femtosecond solution WAXS: bond formation and solvent coordination

van Driel, T., et al. Nat. Commun. 7, 13678 (2016)

[Ir2(dimen)4]2+ Q (Å-1)

[Au(CN)-2]3

K. Kim, et al. Nature 518, 385 (2015)


Further examples for femtosecond solution WAXS: vibrational wavepacket dynamics

K. Kunnus et al., Nat. Commun. 11, 634 (2020) K. Haldrup et al., Phys. Rev. Lett. 122, 063001 (2019)

Fe-carbenes PtPOP


High photon energy at European XFEL

8 x Si(531)

~ 77 mm

LaB6 diffraction collected with LPD @ 20 keV

Unique opportunities at high X-ray energies!

Nb K-edge ~19 keV

Large pixel detector (LPD)

0 ph

1 ph

2 ph

3 ph

ADU

Bin

Cou

nts


FXE instrument and experimental conditions for users

Parameter Unit 1st run 4th run

Photon energy (range)

keV ~ 9 (±0.3) keV) ~ 6 keV – 20 keV

Pulse number/train 1 – 30 1 – 300

Intra-train rep.-rate kHz 1128 1128, 564, 376, etc.

Pulse energy (at source)

µJ ~ 500 up to 4000

Bandwidth % 0.14* ca. 0.20 at 9.3 keV

Pointing stability µrad ~ 2 ~ 2

Focus size µm 10-30 ca. 8

Timing jitter (fwhm) fs 300 70

* calculated/simulated


FXE instrument: pump-probe results and user experiments


Pump-probe X-ray emission spectroscopy on [Fe(bpy)3]- in aqueous solution

Kβ

Kα

Fe Kα difference spectra

Time delay / ps

IRF2 ≈ jitter2 + pulse width2 + GVM2

113 fs 70 fs 50 fs 100 fs

Thinner jets will enable better temporal resolution

Sample: 10 mM solution of [Fe(bpy)3]2+, 100 µm round jet Excitation: 400 nm, 50 fs, 2 µJ/pulse X-ray probe: 9.3 keV, 564 kHz, 100 pulses/train

“Ultrafast X-Ray Photochemistry at European XFEL: capabilities of FXE instrument” D. Khakhulin et al., Appl. Sci., 10(3), 995 (2020)


Femtosecond X-ray emission spectroscopy on [Fe(terpy)2]2+ in aqueous solution

Nax

Neq HS



Large Pixel Detector Scattering from 100 um water jet

Pump-probe X-ray scattering on [Fe(bpy)3]2+ aqueous solution

XFEL: 5 min collection

ESRF: 2 h collection

Sample: 10 mM solution of [Fe(bpy)3]2+, 100 µm round jet Excitation: 400 nm, 50 fs, 2 µJ/pulse X-ray probe: 12 keV, 564 kHz, 90 pulses/train, ~170 µJ/pulse to stay in high gain stage of LPD

Difference scattering curves

“Ultrafast X-Ray Photochemistry at European XFEL: capabilities of FXE instrument” D. Khakhulin et al., Appl. Sci., 10(3), 995 (2020)


Fe Kα Co Kα

Co K-alpha

Fe K-alpha

Simultaneous detection of both Iron Kα and Cobalt Kα emission No uncertainty about t0 and normalization

PI: Matthias Bauer (University of Paderborn) Noble-metal free dyads with FeII photosensitzer

-0,4 -0,2 0,0 0,2 0,4 0,6 0,8 1,0 1,2

-0,030

-0,015

0,000

0,015

0,030

Nor

m. I

nteg

r. C

ount

s - f

it [a

.u.]

Probe delay [ps]

Kα1 middle derived wavepacket Damped sin fit


[S. Mariager, D. Khakhulin et al., NanoLett. (2010)]

Radial Breathing Tbr ~ R / vR

Axial Extension Text ~ L / vL

Bending Tben ~ L2/RvL

Tracking acoustic vibrations in semiconductor NWs by TR-GIXD

0 200 400 600 800

0.0

7.0x10-5

1.4x10-4

2.1x10-4

4 bunch mode (τx-ray≈ 130 ps) hybrid mode (τx-ray≈ 95 ps)

∆a/a

Delay [ps]

[D. Khakhulin et al. Acta Cryst. (2016). A72]

Diamond detector

High speed chopper

Storage ring

X-ray probe 1 kHz, 100 ps

Fast GaAs detector

Sample

dnw = 450 nm


Jungfrau Detector

Sample position

Pump-probe grazing incidence XRD on semiconductor NWs

Tracking the transient lattice strain in NWs by monitoring Bragg peak position vs time delay

9.3 keV, τx-ray ≈ 50 fs rep. rate 10Hz

λ = 515 nm τlas = 0.8 ps rep.rate 10 Hz

Grazing incidence: α ≤ 2°

Jungfrau detector

Beams on sample Burn marks on sample

PI: V. Dubrovskii, ITMO, Russia


Pump-probe GI diffraction with a SASE spectrum of the European XFEL

Single-shot spectrum (HIREX) [by N. Kujala (EuXFEL)]

InAs NW Bragg peak position variations shot-to-shot

Average spectrum over 1100 shots

Delay scan

Delay [ps]

Courtesy of R. Kurta (EuXFEL)

PI: V. Dubrovskii, ITMO, Russia


Summary Combined measurements of fs hard X-ray emission and solution scattering

are possible at FXE and result in high quality data with temporal resolution

down to 100 fs even without timing jitter correction

Performed FXE’s first fs X-ray emission spectroscopy and diffraction

experiments on solids both in transmission and grazing incidence geometry.

Development of specific instrumentation and advances sample environment is

ongoing

Upcoming commissioning campaigns are focused on developing advanced X-

ray absorption spectroscopy as well as 2D photon in/photon out

spectroscopies such as RXES (Johann spectrometer)

Check the status at www.xfel.eu/facility/instruments/fxe and subscribe to FXE newsletter


FXE group (EuXFEL) Christian Bressler Mykola Biednov Andreas Galler (now XO) Wojciech Gawelda Katharina Kubicek Frederico Lima Peter Zalden Angel Rodriguez-Fernandes Yifeng Jiang Martin Knoll Paul Frankenberger Timo Korsch Graduate students Christina Bömer Michael Diez Tae Kyu Choi Florian Otte

Acknowledgements EPFL Majed Chergui Camila Bacellar Oliviero Cannelli Dominik Kinschel Giulia Mancini Rebecca Ingle Uni Paderborm: Matthias Bauer Marina Huber ITMO Vladimir Dubrovskii Rodion Reznik George Cirlin

Hamburg (DESY/EuXFEL) Maria Naumova Aleksandr Kalinko Ruslan Kurta Naresh Kujala Wigner Budapest Zoltán Németh György Vankó

ESRF Michael Wulff Denis Leshchev

ELI-ALPS/DESY Sophie Canton Uni Geneva Latévi Max Lawson Daku

Uni Warsaw Jerzy Antonowicz Ryszard Sobierajski


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