Time-Resolved Atomic and Molecular Dynamics
in XUV and IR Laser Fields
Robert Moshammer
Max-Planck-Institut für Kernphysik
Heidelberg
Outline
Part 2: Atoms and Molecules in Intense XUV Fields
• Free-Electron Lasers
- Working Principle and Parameters
• Non-Linear XUV-Atom Interaction
- Two Photons and Two Electrons: Double Ionization
• XUV-Pump – XUV-Probe Experiments
- Pulse Characterization via Autocorrelation
- “Watching” the Decay of Excited Molecules
- Charge Rearrangement in Dissociating Molecules
• XUV-Pump – THz-Probe
- Towards few fs Time-Resolution
Free-Electron Lasers (FEL's)
Light pulses that are
• very intense (1016 W/cm2 and more),
• very short (10 fs),
• very energetic (10 eV…10,000 eV).
AR
S
n
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o
h
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ev
!
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e
c
cien
Working principle:
A moving charge (electron) emits radiation => Synchrotron
Coherently emitting charges act like a laser => FEL
Light-sources:
Synchrotrons and FEL’s
First (accidental) observation in 1947
General Electric Research Lab. NY.
Test of a 70 MeV Synchrotron
accelerator for electrons.
Unexpected losses of energy:
„Schwinger"-radiation
Synchrotron radiation
Lorentz transformation
Rest frame
Laboratory frame
(fast electron v ≈ c)
(slow electron v << c)
θ = 1/γ = moc2/E
θ = 0.64 mrad (6.4 mm spot after 10 m)
for 800 MeV electrons (v = 0.9999998.c)
Synchrotron radiation
dN/dt [1/s]
broad frequency spectrum
ω < 3.γ3.ωo ; ωo = c/R
1013
Radiation from
dipole magnet
(bending radius R)
1011
Ee = 800 MeV
Ie = 200 mA
R=2m
109
0.1
1
10
λ (nm)
100
1000
Wigglers & Undulators
B-field: few Tesla
period: few cm
number: 10...100
gap: cm
Θ = 1/γ
α
K = α / Θ = α.γ ~ B.λu
for K < 1 coherent superposition => Undulator
for K > 1 non-coherent addition => Wiggler
caution: not necessarily constructive interference
the "good” ones
From Synchrotron-Radiation to FEL-Light
Bunch with
Ne electrons
Undulator
Synchrotron-Radiation
N
ee
N
≈
≈
tityy
i
s
s
n
IInntteen
From Synchrotron-Radiation to FEL-Light
Bunch with
Ne electrons
Undulator
L ≈ 30 m
FEL-Radiation
tityy
i
s
n
s
IInntteen
22
≈≈NNee
Self Amplified Spontaneous Emission (SASE)
From Synchrotron-Radiation to FEL-Light
FLASH Undulator
Length:
27 m
Beam Energy: 1 GeV
From Synchrotron-Radiation to FEL-Light
FEL
7 orders of
magnitude!
Lasers
HHG
From Synchrotron-Radiation to FEL-Light
• FLASH: 2005
• LCLS: 2009
• Japan: 2011
• FERMI: 2012
• XFEL: 2016
The European X-FEL : 2016
• intensity:
~ 1013 . . . 1021 W/cm2
• photon energies: ~ 200 . . . 10.000 eV
The European X-FEL : 2016
3 .5
km
Driving vision: Imaging of Bio-Molecules
• X-FEL, DESY
• LCLS, SLAC
• SACLA, Japan
- 1013 photons
- 10 keV
- 10 fs pulse
X-ray
image
~1021 W/cm2
Hajdu, Chapman
Measure before destruction !
The Free-Electron Laser at Hamburg (FLASH)
• Intensity:
• Photon energy:
• Pulse length:
• Rep. rate:
~ 1013 . . . 1017 W/cm2
~ 20 . . . 250 eV
~ 30 . . . 200 fs
~ 300 Hz . . . (30 kHz)
Reaction Microscope at FLASH
nd
a
-1-111 toorrrr)) and
((<<1100 -9t torr) !!!!
m
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u
vaaccuum <10 -9 torr)
nntt v
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tsts((<10
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vveery
Reaction Microscope at FLASH
Outline
Part 2: Atoms and Molecules in Intense XUV Fields
• Free-Electron Lasers
- Working Principle and Parameters
• Non-Linear XUV-Atom Interaction
- Two Photons and Two Electrons: Double Ionization
• XUV-Pump – XUV-Probe Experiments
- Pulse Characterization via Autocorrelation
- “Watching” the Decay of Excited Molecules
- Charge Rearrangement in Dissociating Molecules
• XUV-Pump – THz-Probe
- Towards few fs Time-Resolution
Two-Photon Double Ionization of He
direct transition
He0 → He++
0
e2
Ehν = 44 eV
-40
I ≈ 1014 W/cm2
1s2
-80
Energy (eV)
e1
Helium
Two-Photon Double Ionization of He
direct transition
total cross section (theory)
He0 → He++
0
e2
Ehν = 44 eV
I ≈ 1014 W/cm2
ring ?
a
h
s
y
g
r
e
n
Electron e
tion ?
la
e
r
r
o
c
r
Angula
1s2
P. Antoine et al., PRA 78 (2008)
-40
-80
Energy (eV)
e1
Helium
Two-Photon Double Ionization of He
Photo-Ionization
e1
e2
Ion momentum pion
Two-Photon Double Ionization of He
Ion momentum pion
Photo-Ionization
e1
e2
pion = -Σpe
Two-Photon Double Ionization of He
Ion momentum pion
Photo-Ionization
e1
e2
pion = -Σpe
ε
One photon: He1+
Two-Photon Double Ionization of He
Photo-Ionization
Synchrotron
ε
hν > 80 eV
e1
e2
pion = -Σpe
ε
E = 44 eV
I ≈ 1014 W/cm2 , Tpuls ≈ 25 fs
Two photons:
He2+
One photon: He1+
Two-Photon Double Ionization of He
Photo-Ionization
Synchrotron
ε
hν > 80 eV
e1
e2
pion = -Σpe
ε
Two photons:
He2+
One photon: He1+
Two-Photon Double Ionization of He
Photo-Ionization
Synchrotron
ε
hν > 80 eV
e1
e2
pion = -Σpe
ε
Two photons:
He2+
One photon: He1+
Two-Photon Double Ionization of He
Photo-Ionization
Synchrotron
ε
hν > 80 eV
e1
e2
pion = -Σpe
ε
Two photons:
He2+
One photon: He1+
Two-Photon Double Ionization of He
Photo-Ionization
Synchrotron
ε
hν > 80 eV
e1
e2
pion = -Σpe
ε
Theory
A. Kheifets
Two photons:
He2+
1+2+
One
Two photon:
photons:He
He
Two-Photon Double Ionization of He
Photo-Ionization
Synchrotron
ε
hν > 80 eV
e1
e2
pion = -Σpe
ε
Theory
E. Foumouo & B. Piraux
Two photons:
He2+
Two photons: He2+
Two-Photon Double Ionization of He
Photo-Ionization
Synchrotron
ε
hν > 80 eV
e1
e2
pion = -Σpe
ε
Theory
C. W. McCurdy et al.
Two photons:
He2+
2+ 2+
One
photon:
He
Two photons: He
Two-Photon Double Ionization of He
total cross section (theory)
44 eV
52 eV
57 eV
D. Horner et al., PRA 76 030701 (R) (2007)
Two-Photon Double Ionization of He
He++
44 eV
He+
1s2
direct
52 eV
sequential
He++
57 eV
He+
1s2
D. Horner et al., PRA 76 030701 (R) (2007)
Two-Photon Double Ionization of He
44 eV
44 eV
52 eV
2
52 eV
Py [au]
1
0
57 eV
-1
-2
-2
-1
0
1
2
Px [au]
D. Horner et al., PRA 76 030701 (R) (2007)
Two-Photon Double Ionization of He
Theory:
J. Feist et al, 2010
D. Horner et al, 2010
Theory folded
with exp. resol.
tatatutuss: :
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M. Kurka et al., New J. Phys. 12 (2010)
Outline
Part 2: Atoms and Molecules in Intense XUV Fields
• Free-Electron Lasers
- Working Principle and Parameters
• Non-Linear XUV-Atom Interaction
- Two Photons and Two Electrons: Double Ionization
• XUV-Pump – XUV-Probe Experiments
- Pulse Characterization via Autocorrelation
- “Watching” the Decay of Excited Molecules
- Charge Rearrangement in Dissociating Molecules
• XUV-Pump – THz-Probe
- Towards few fs Time-Resolution
XUV-Pump – XUV-Probe setup
Split Mirror
FEL-pulse
delay
Goal
What happens with a (small) molecule after ionization (excitation)?
“Watch” the dynamical evolution (electrons and nuclei)!
Scales:
• Time in the order of 10 – 100 fs
• Excitation energies from 10 – 100 eV (XUV)
Approach:
• Use intense fs XUV pulses
• Pump-probe experiments
excitation
Aim:
• Dynamics and structure
• High temporal resolution
What XUV Intensity is needed ??
Consider a single molecule (cross-section σ):
Probability to excite (pump) and/or probe the molecule:
• Do both steps with at least 10% efficiency !!
Ppump ≈ Pprobe
 Intesity 
= σ ⋅
 ⋅ T pulse ≈ 0.1
 hν 
What XUV Intensity is needed ??
Consider a single molecule (cross-section σ):
Probability to excite (pump) and/or probe the molecule:
• Do both steps with at least 10% efficiency !!
Ppump ≈ Pprobe
 Intesity 
= σ ⋅
 ⋅ T pulse ≈ 0.1
 hν 
13
22 (for σ = 1 Mb)
13
Intensity
≈
10
W/cm
Intensity ≈ 10 W/cm (for σ = 1 Mb)
We don’t want to pump molecule A and probe molecule B !!
=> only one molecule at a time (very dilute gas-target)
First Step: Characterization of FEL Pulses
e-
eIonization of an atom
(non-linear detector)
e-
Ionization yield
Autocorrelation trace
=> Pulse length
0
delay
Remarks about the FLASH Pulse Structure
Remarks about the FLASH Pulse Structure
8.0E-5
Simulated pulses
based on:
• Spectral shape
• Pulse duration
7.0E-5
6.0E-5
5.0E-5
4.0E-5
3.0E-5
2.0E-5
1.0E-5
0.0E+0
-50.0 -40.0
-20.0
0.0
20.0
40.0 50.0
time [fs]
T. Pfeifer at al., Optics Lett. 35 (2010)
Remarks about the FLASH Pulse Structure
2.2E-5
Simulated pulses
based on:
• Spectral shape
• Pulse duration
2.0E-5
1.7E-5
1.5E-5
1.2E-5
1.0E-5
7.5E-6
5.0E-6
2.5E-6
0.0E+0
-50.0 -40.0
-20.0
0.0
20.0
40.0 50.0
time [fs]
T. Pfeifer at al., Optics Lett. 35 (2010)
Remarks about the FLASH Pulse Structure
6.0E-5
Simulated pulses
based on:
• Spectral shape
• Pulse duration
5.0E-5
4.0E-5
3.0E-5
2.0E-5
1.0E-5
0.0E+0
-50.0 -40.0
-20.0
0.0
20.0
40.0 50.0
time [fs]
T. Pfeifer at al., Optics Lett. 35 (2010)
Remarks about the FLASH Pulse Structure
1.0E-4
Simulated pulses
based on:
• Spectral shape
• Pulse duration
8.0E-5
6.0E-5
4.0E-5
2.0E-5
0.0E+0
-50.0 -40.0
-20.0
0.0
20.0
40.0 50.0
time [fs]
T. Pfeifer at al., Optics Lett. 35 (2010)
Remarks about the FLASH Pulse Structure
3.0E-5
Simulated pulses
based on:
• Spectral shape
• Pulse duration
2.5E-5
2.0E-5
1.5E-5
1.0E-5
5.0E-6
0.0E+0
-50.0 -40.0
-20.0
0.0
20.0
40.0 50.0
time [fs]
T. Pfeifer at al., Optics Lett. 35 (2010)
Remarks about the FLASH Pulse Structure
3.0E-5
Simulated pulses
based on:
• Spectral shape
• Pulse duration
2.5E-5
2.0E-5
1.5E-5
1.0E-5
5.0E-6
0.0E+0
-50.0 -40.0
-20.0
0.0
20.0
40.0 50.0
time [fs]
T. Pfeifer at al., Optics Lett. 35 (2010)
Remarks about the FLASH Pulse Structure
7.0E-5
Simulated pulses
based on:
• Spectral shape
• Pulse duration
6.0E-5
5.0E-5
4.0E-5
3.0E-5
2.0E-5
1.0E-5
0.0E+0
-50.0 -40.0
-20.0
0.0
20.0
40.0 50.0
time [fs]
T. Pfeifer at al., Optics Lett. 35 (2010)
Remarks about the FLASH Pulse Structure
4.5E-5
4.5E-5
Simulated
pulses
4.0E-5
based
3.5E-5 on:
• 3.0E-5
Spectral shape
• 2.5E-5
Pulse duration
4.0E-5
3.5E-5
3.0E-5
2.5E-5
2.0E-5
1.5E-5
1.0E-5
2.0E-5
coherence length
5.0E-6
average pulse length
0.0E+0
-50.0 -40.0
1.5E-5
1.0E-5
-20.0
0.0
20.0
40.0 50.0
time [fs]
5.0E-6
0.0E+0
-50.0 -40.0
-20.0
0.0
20.0
40.0 50.0
time [fs]
T. Pfeifer at al., Optics Lett. 35 (2010)
Non-linear Autocorrelation (38 eV, FLASH)
Multiple Ionization of N2 in Pump-Probe
4th order Autocorrelation
(n=4 photon transition)
40
40 ±10
±10 fs
fs
55 ±1
±1 fs
fs
Y. Jiang et al., PRA 82 (2010)
T. Pfeifer at al., Optics Lett. 35 (2010)
Non-linear Autocorrelation (38 eV, FLASH)
Multiple Ionization of N2 in Pump-Probe
EExxaam
mppllee::
aavv.. ppulse th
ulse l4leennorder
Autocorrelation
g
t
h
g
≈
t
h
44transition)
0
ccoohheerenc (n=4 photon
≈
rencee lleenngth 0 ffss
gth ≈≈ 55 ffss
K. Meyer et al., PRL 108 (2012)
T. Pfeifer at al., Optics Lett. 35 (2010)
“Typical” Autocorrelation Traces @ FLASH
Multiple Ionization of Argon (28 eV)
High electron-bunch charge (~ 0.4 nC)
aavveerraagge pulse
e pulsele
lennggth
th≈≈220000 fs
fs
Low electron-bunch charge (~ 0.1 nC)
average
averagepulse
pulselength
length≈≈80
80fs
fs
Pump – Probe with D2
60
Probe
40
Energy (eV)
D+ + D+
Pump
1/R
30
20
1sσg
D2+
10
0
D2
0
1
2
R (a.u.)
3
4
KER
50
Eph = 38 eV
Pump – Probe with D2
Eph = 38 eV
delay (fs)
60
10
20
30
40
50
60
Probe
80
25
20
D+ + D+
Pump
40
KER
50
Energy (eV)
70
15
10
1/R
5
30
KER (eV)
20
1sσg
D2+
10
0
D2
0
1
2
3
4
R (a.u.)
Y. Jiang et al., PRA 81 (2010)
Pump – Probe with D2
Eph = 38 eV
delay (fs)
60
10
20
30
40
50
60
70
80
Probe
20
D+ + D+
Pump
40
KER
50
15
10
1/R
5
30
20
1sσg
D2+
10
Yield
Energy (eV)
25
0
0
D2
0
1
2
3
10
20
30
40
delay (fs)
4
R (a.u.)
Y. Jiang et al., PRA 81 (2010)
50
60
70
80
Pump – Probe with D2
Eph = 38 eV
delay (fs)
60
10
20
30
40
50
60
70
80
Probe
25
20
50
15
10
1/R
5
30
20
1sσg
D2+
10
Yield
Energy (eV)
40
KER
!
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Dire
D+ + D+
Pump
0
0
D2
0
1
2
3
10
20
30
40
delay (fs)
4
R (a.u.)
Y. Jiang et al., PRA 81 (2010)
50
60
70
80
Pump – Probe with D2
Eph = 38 eV
delay (fs)
10
20
30
40
50
60
70
80
25
KER
20
15
10
Yield
5
0
Calculation with δ probe-pulse
(F. Martin)
10
20
30
40
delay (fs)
50
60
70
80
Pump – Probe with D2
Eph = 38 eV
delay (fs)
10
20
30
40
50
60
70
80
25
KER
20
15
10
Yield
5
0
5 fs pulses
a simple model
K. Meyer et al., PRL 108 (2012)
10
20
30
40
delay (fs)
50
60
70
80
Pump – Probe with D2
Eph = 38 eV
delay (fs)
10
20
30
40
50
60
70
80
25
KER
20
15
10
Yield
5
0
40 fs pulses
a simple model
K. Meyer et al., PRL 108 (2012)
10
20
30
40
delay (fs)
50
60
70
80
Pump – Probe with D2
Eph = 38 eV
delay (fs)
10
20
30
40
50
60
70
80
25
20
Yield
KER
15
!
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t
s
t
AAtto
0
40 fs “spiky” pulses
a simple model
K. Meyer et al., PRL 108 (2012)
10
20
30
40
delay (fs)
50
60
70
80
Outline
Part 2: Atoms and Molecules in Intense XUV Fields
• Free-Electron Lasers
- Working Principle and Parameters
• Non-Linear XUV-Atom Interaction
- Two Photons and Two Electrons: Double Ionization
• XUV-Pump – XUV-Probe Experiments
- Pulse Characterization via Autocorrelation
- “Watching” the Decay of Excited Molecules
- Charge Rearrangement in Dissociating Molecules
• XUV-Pump – THz-Probe
- Towards few fs Time-Resolution
Decay of an Excited Molecule (Cluster)
From atom to molecule
60 eV
2p
2s
1s
Ne atom
Decay of an Excited Molecule (Cluster)
From atom to molecule
2p
2s
1s
Ne+ ion
Fluorescence photon
(time: pico…nanoseconds)
Decay of an Excited Molecule (Cluster)
From atom to molecule
2p
2p
2s
1s
2s
Fluorescence photon
(time: pico…nanoseconds)
Ne+ ion
1s
Ne atom
Very (infinitely) large distance
Decay of an Excited Molecule (Cluster)
From atom to molecule
2p
2p
2s
2s
1s
1s
Ne+ ion
Ne atom
Few atomic radii
Decay of an Excited Molecule (Cluster)
From atom to molecule
2p
2p
2s
2s
1s
1s
Ne+ ion
Neon
Ne atom
dimer
Few atomic radii
Decay of an Excited Molecule (Cluster)
Interatomic Coulombic Decay (ICD)
From atom to molecule
First theoretical prediction in 1997
2p
2s
2p
2s
• First exp. observation in 2003
1s (Marburger et al. PRL 90,1s
Jahnke et al. PRL 93)
• More than 200 publications on ICD
• Dominant channel in all Van-der-Waals and Hydrogen-bonded
systems (water).
Neon dimer
• Source of low-energy electrons in tissue => radiation damage.
• ICD
lifetime
is notradii
measured !!
Few
atomic
Decay of an Excited Molecule (Cluster)
From atom to molecule
goal:
goal:
decay-time
decay-time of
of ICD
ICD in
in Ne
Ne22 !!!!
2s
1s
2p
method:
method:
2s
XUV-XUV
XUV-XUV pump-probe
pump-probe
1s
2p
prediction
nonuclear
nuclearmotion
motion):
):
prediction (theory,
(theory, no
85
85 fs
fs Santra
Santra&&Cederbaum,
Cederbaum,JCP
JCP115
115(2001)
(2001)
168
fs
&&Cederbaum,
168
fs Vaval
Vaval
Cederbaum,JCP
JCP126
126(2007)
(2007)
Neon
dimer
Few atomic radii
Interatomic Coulombic Decay (ICD)
Ne2+
/
Ne+
Ne+ / Ne
Ne+ / Ne+
Ne / Ne
Ne2
Interatomic Coulombic Decay (ICD)
Ne2+
/
Ne+
Ne+ / Ne
pump
1 photon
Ne+ / Ne+
Ne / Ne
Ne2
Interatomic Coulombic Decay (ICD)
Ne2+
ICD
pump
1 photon
/
Ne+
Ne+ / Ne
Ne+ / Ne+
Ne / Ne
Ne2
Interatomic Coulombic Decay (ICD)
probe
1 photon
Ne2+
ICD
pump
1 photon
/
Ne+
Ne2
2+
++
2+ // Ne
Creation
of
Ne
Creation
of
Ne
Ne
Ne+ / Ne
only
only after
after ICD
ICD has
has happened
happened
=>
=>
/ Ne+
Ne+
2+
+
Increase
Increase of
of Ne
Ne2+ // Ne
Ne+ yield
yield
with
pump-probe delay
delay time.
time.
Newith
/ Ne pump-probe
Interatomic Coulombic Decay (ICD)
probe
1 photon
KER vs. delay for Ne2+ / Ne+ pairs
Ne2+ / Ne+
ICD
pump
1 photon
Ne+ / Ne
Ne+ / Ne+
KER: Ion kinetic energies
Ne / Ne
Interatomic Coulombic
Decay
(ICD)
First
First m
meeaassuurreem
meenntt ooff IIC
CD
D llififeettiim
mee !!
Yield of Ne2+ / Ne+ pairs
TICD = 150 ± 50 fs
K. Schnorr et al.,
PRL 111 (2013)
Interatomic Coulombic Decay (ICD)
Comparison with theory (S. Scheit, V. Averbukh)
FFuuttuurree
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Outline
Part 2: Atoms and Molecules in Intense XUV Fields
• Free-Electron Lasers
- Working Principle and Parameters
• Non-Linear XUV-Atom Interaction
- Two Photons and Two Electrons: Double Ionization
• XUV-Pump – XUV-Probe Experiments
- Pulse Characterization via Autocorrelation
- “Watching” the Decay of Excited Molecules
- Charge Rearrangement in Dissociating Molecules
• XUV-Pump – THz-Probe
- Towards few fs Time-Resolution
Multiple Ionization of Atoms
Photon energy: hν
ν ~90 eV
Intensity: 2×1015 W/cm2
hν
Xenon
Giant or shape resonance in Xe
ee-
4d
5s,p
Andersen et al.
J. Phys. B
34, 2009
(2001)
Multiple Ionization of Xe
From Atoms to Molecules: Xe => Iodine
Goal:
Radiation damage
(multiple ionization and
fragmentation of
molecules, Iodine as
model system)
Photon energy: hν
ν ~90 eV
Intensity: 2×1015 W/cm2
Xenon
ee-
Iodine (I2) e
e-
4d
5s,p
4d
5s,p
R(t)
ee-
Multiple Ionization of Xe
85 eV
~ 1014 W/cm2
5+
4+
3+
2+
6+
1+
7+
Multiple Ionization of Xe and Iodine
85 eV
~ 1014 W/cm2
Time of flight ion2 (ns)
Single FEL pulse
I5++I4+
I5++I3+
5+
I6++I4+
4+
3+
2+
6+
n
o
ti
rp
o
s
b
n
A
o
l
a
ti
ti
rp
n
o
e
s
u
b
q
A
SSeequential
!
s
n
to
o
h
7+
P
!
5
s
1
n
to
to
o
p
h
u
P
f
oof up to 15
1+
I4++I4+
I7++I6+
I5++I5+
I6++I6+
I8++I7+
I7++I7+
Time of flight ion1 (ns)
Multiple Ionization of Dissociating Iodine
XUV-XUV pump–probe
Q1Q2 =3
=2
=1
Potential energy V [eV]
...
100
2
Q1 ⋅ Q2 pion
V≈
=
= Ekin
2M
R
80
iodine (I2)
60
e- ee- e-
40
eeee-
4d
5s,p
R(t)
20
0
5
I2 equilibrium
bond length
10
15
20
25
Internuclear distance [a.u.]
30
Multiple Ionization of Dissociating Iodine
Kinetic energy release (KER) [eV]
I2+/I2+ coincidence channel
30
intermediate
state(after pump)
20
2+/2+ (21.8 eV)
10
1+/2+(10.9 eV)
1+/1+ (5.4 eV)
0
-2000 -1500 -1000 -500
20
0
500 1000 1500 2000
I1+/I2+ coincidence channel
1+/2+(10.9 eV)
10
0
-2000 -1500 -1000 -500
20
0
500 1000 1500 2000
I1+/I1+ coincidence channel
10
1+/1+ (5.4 eV)
0
-2000 -1500 -1000 -500
0
500 1000 1500 2000
Time delay [fs]
Multiple Ionization of Dissociating Iodine
Kinetic Energy Release KER [eV]
I3+/I4+
coincidence channel
100
intermediate
state(after pump)
80
3+/4+
60
3+/3+
40
2+/3+
20
1+/2+
0
-2000 -1500 -1000 -500
0
500
Time delay [fs]
1000 1500 2000
Multiple Ionization of Dissociating Iodine
Kinetic Energy Release KER [eV]
I1+/I4+
coincidence channel
intermediate
state(after pump)
100
80
'hole':
no counts near time overlap
60
40
1+/4+
20
1+/2+
0
-2000 -1500 -1000 -500
0
500
Time delay [fs]
1000 1500 2000
Multiple Ionization of Dissociating Iodine
Over-Barrier (OVB) Charge Transfer
H. Ryufuku, K. Sasaki, and T. Watanabe, PRA 21, 745 (1980)
A. Niehaus, J. Phys. B 19, 2925 (1986)
I1+
I4+
e-
e-
R
Over-Barrier (OVB) Charge Transfer
H. Ryufuku, K. Sasaki, and T. Watanabe, PRA 21, 745 (1980)
A. Niehaus, J. Phys. B 19, 2925 (1986)
I1+
I4+
e-
e-
R
I1+
e-
I4+
e-
Multiple Ionization of Dissociating Iodine
I1+/I3+ coincidence channel
Kinetic Energy Release KER [eV]
30
over-barrier transfer 'hole':
channel closed
20
OVB-model
10
0
30
experiment
20
10
0
-2000 -1500 -1000 -500
0
500 1000 1500 2000
Time delay [fs]
Multiple Ionization of Dissociating Iodine
Quantitative Comparison
critical Rc (a.u.)
16
OVB model
experiment
14
••th
rtantnt
porta
impo
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ming
“timi
thee“ti
ininmu
tionn
izatio
ioniza
ltipleleion
multip
12
an
andd
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lon
ted
bu
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dis
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ar
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lon
ron
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tri
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ion
los
xp
nn(e
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dis
ion
re
los
fo
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be
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tio
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so
before dis
10
8
3
4
5
6
charge pairs (1,Q)
The FEL and Laser Group at the MPIK
G. Schmid
P. Cörlin
A. Sperl
K. Schnorr
L. Fechner
A. Fischer
N. Camus
M. Schönwald
A. Senftleben
C.D. Schröter (now Uni. Kassel)
MSc & BSc Students:
A. Krupp
J. Kunz
A. Broska …
Thanks to:
Max-Planck-Institute, Heidelberg
Y. Jiang, M. Kurka, B. Knape, K. Meyer, C. Kaiser, J. Ullrich, T. Pfeifer
MPQ, Garching
M. Kübel, M. Kling…
(Former) ASG of MPG, Hamburg
A. Rudenko, L. Foucar, D. Rolles, R. Boll, D. Anielski…
Tohoku University,Sendai
K. Ueda…
DESY FEL-group
N. Stojanovic, A. Al-Shemmari, R. Treusch, S. Düsterer,
M. Gensch, G. Brenner, ….
and many more …

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