Ultrafast Molecular Spectroscopy

Marcus Motzkus, Physikalisch‐Chemisches Institut Universität Heidelberg

IMPRS –QD Workshop 30.09.2013 –MPI für Kernphysik time scales in science

http://www.gettyimages.com/detail/89516567/Photographers‐Choice http://en.wikipedia.org/wiki/File:WMAP_2008.png

shortest man‐made flash/pulse of light age of the universe 80 attoseconds 1 second 14 billion years

electronic human/biological timescale timescale molecular geological/astronomical timescale timescale cameras laser pulses Adapted from T. Pfeifer, MPI-K

Ultrafast Molecular Spectroscopy

Outline

I. Intro - Ultrafast Molecular Spectroscopy - Time scale of chemical processes, Overview of methods - Pump-probe principle - seminal experiments, applications - wavepackets

II. Optical Methods of Pump-Probe-Spectroscopy - Transient Absorption: Population dynamics -Examples - Problem of overlapping resonances

III. Multidimensional spectroscopy - Case study: dynamics on Carotenoids - Pump-dump-spectroscopy - Pump-DFWM - Quantum control spectroscopy “not observable” fast processes: slow‐motion movie

(Eadweard Muybridge, “The Horse in Motion”, 1878) 'Doc' Edgerton - Strobe Photography

Harold Edgerton MIT, 1942

“How to Make Apple sauce at MIT”, 1964

 Time Resolution: a few microseconds Ultrafast lasers ~4 fs pulse Active mode locking

1000

Passive mode locking

100 Colliding pulse mode locking

Intra-cavity pulse 10 Extra-cavity pulse compression compression Baltuska et al. 2001 Shortest Pulse Duration (femtoseconds)

'65 '70 '75 '80 '85 '90 '95 Year

Ultrafast Ti:sapphire laser Transitions in a molecule v = 1 J = 4 UV‐VIS‐Spectroscopy Rotation‐ s] S

15 4 ‐ Internal conversion Spectroscopy S J = 3 3 [10‐14 s]

J = 2

Rotational states J = 1 Tn J = 0 Excitation [10 v = 0 IR‐ & NIR‐ S2 Spectroscopy Intersystem crossing

T v = 4 1

v = 3 Fluorescence Phosphorescence ‐9 ‐3

Vibrational states [10 s] [10 s] v = 1

v = 0 IPC Friedrich‐Schiller‐M. S0 8 Schmitt ‐ Universität Jena Frequency conversion with nonlinear optics: (2) ‐ Processes Second harmonic generation:

Sum frequency generation:

Difference frequency generation: From: Spectra‐Physics Continuum Generation

Continuum Generation: focusing a femtosecond pulse into a clear medium turns the pulse white.

Generally, small‐scale self‐focusing occurs, causing the beam to break up into filaments.

Recently developed techniques involving optical fibers, hollow fibers, and microstructure fibers produce very broadband continuum, over 500 THz (1000 nm) in spectral width!

From R. Trebino, GaTech Supercontinuum Generation in a Photonic Crystal Fiber (PCF)

PCF   100 fs (TL) >1 ps (chirped)  = 9 nm @ 800 nm  > 600 nm

Photo from www.bath.ac.uk/physics. Ultrafast Spectroscopy: Pump and Probe

Probe pulse

E (t–) Pr Sample Esig(t,) medium Detector E (t) Variable pu Temporal duration Path delay,  Pump 1 ns  30.0 cm pulse 1 ps  0.3 mm 4 fs  1.2 m (Temporal duration corresponds to the time it takes for the pulse to travel along the path which is set by the variable delay stage) The excite and probe pulses can be different colors. First fs-observation of a transition state: ICN-Dissociation

V2 V1 “Detection”

V0 I + CN*

* = 391,4 nm   = 390,4 nm * *= 389,8* = 389,7 nm nm = 388,5 nm

0I + CN



Potentielle Energie Potentielle ICN

“Start”

250300350400600 InternuclearAbstand separation I-CN [pm] I-CN [pm]

M.J. Rosker et al., J. Chem. Phys. 89 (1988) 6113 Pump‐Probe Femtosecond Experiment (Zewail lab) Real‐time observation of wavepacket dynamics in a dissociation reaction

Na* + I Na+ I‐ ‐ Na I Na+ I  + ‐  pr* pr Ionic: Na + I pr energy

Covalent: Na + I pr* Avoided crossing Potential

.... . = NaI* [Na I] Na + I + Etrans

Rx = 6.93 Å Internuclear separation Paradigma: Chemical bond in a two‐atomic molecule NaI changes its character (covalent or ionic) with time before dissociation into Na‐ and I‐atoms takes place (bond forms again after an electron was transferred).

T.S. Rose et al. –J. Chem. Phys. 88 (1988) 6672 Femtochemistry

1999 Nobel Prize in Chemistry

Ahmed H. Zewail

"for his studies of the transition states of chemical reactions using femtosecond spectroscopy" http://nobelprize.org/ Probing of vibrational dynamicsin real-time

Potential Energy V V 0 1 V 2  delay Time Pump

 Coordinate Probe Pump  Probe time Wavepacket Coherence Superposition of time‐dependent wavefunctions excited by short (broadband) laser pulse gives oscillating wavepacket.

n = 22 Uncertainty relation in two n = 21 equivalent forms: h n = 20 space, impulse ∆x  ∆p  n = 19 2π h n = 18 energy, time ∆E  ∆t  n = 17 2π n = 16 n = 15 Example for uncertainty n = 14 of laser pulses:

1 Laser pulse ∆t  50 fs  ∆E  1kJ mol h ∆E  ∆t  n = 1 ∆t  10 fs  ∆E  6 kJ mol 1 2π n = 0 Wavepacket Coherence Shorter Laser pulse  broader laser spectrum  better localised wavepacket

n = 22 Uncertainty relation in two n = 21 equivalent forms: h n = 20 space, impulse ∆x  ∆p  n = 19 2π

We llenpak et(WP) gewilauf mWchtet indes Et -Unscellpak härfe dest L aser-Pulse ergibt

n 2=

n 12= 90 Unschä zweiin F rfelatomuliionerug

n 1= 78 x∆ p∆ h2π

h n 1= 56 E∆ 2t∆ π

E∆Laserpuls*t∆ π2 n 1= 4

=1n n =0n n = 18 h max energy, time ∆E  ∆t  n = 17 2π n = 16 n = 15 Example for uncertainty n = 14 of laser pulses:

1 Laser pulse ∆t  50 fs  ∆E  1kJ mol h ∆E  ∆t  n = 1 ∆t  10 fs  ∆E  6 kJ mol 1 2π n = 0 Laser mode locking vs. Vibrational wave packet

Laser resonator Harmonic potential

1 1 D 2  = 2( )  = c/2L

One mode One eigenstate single-mode operation time-independent E minimal E minimal

Mode locking: Coherent superposition:

N N

Trepetition = 1/ Toscillation = 1/ Time-bandwidth product Uncertainty relation Concept of wavepackets

Quantum mechanics Stationary wavefunctions extending over a relatively large region of space

Classical mechanics  Moving point objects; Localization but is it valid?

Erwin Schrödinger, “Der kontinuierliche Übergang von der Mikro zur Makromechanik,” Die Naturwissenschaften, Heft 28, 9.7.1926, 664‐660: (Translation) ...I show, that a group of eigenmodes with high quantum number n and relatively small differences in their quantum numbers describe a point mass which moves according to usual mechanics... E ‐i n t (x,t) =  anne h the reflects wavepacket Vibrational

nuclei

classic

movement oeetvbaindynamics vibration Coherent

Fluorescence Intensity aeaktdnmc in dynamics Wavepacket R.M. omnet Bowman al.

–Chem.

h B the

Phys. ‐ tt fI of state

Lett.

161 (1989) 2

297 Potential energy curves of Na2‐molecule and schematic representation of wavepacket dynamics

T. Baumert, Universität Kassel Pump-probe: Time-resolved photoelectron spectroscopy

Visualizing wave packet motion

Left: Measured photoelectron distribution of Na2 as a function of the pump‐probe delay. The kinetic energy of the photoelectrons has been transformed to the internuclear distance. Right: Classical oscillation of a molecule consisting of two atoms.

T. Baumert, University of Kassel Ultrafast Molecular Spectroscopy

Outline

I. Intro ‐ Ultrafast Molecular Spectroscopy ‐ Time scale of chemical processes, Overview of methods ‐ Pump‐probe principle ‐ seminal experiments, applications ‐ wavepackets

II. Optical Methods of Pump‐Probe‐Spectroscopy ‐ Transient Absorption: Population dynamics ‐ Examples ‐ Problem of overlapping resonances

III. Multidimensional spectroscopy ‐ Case study: dynamics on Carotenoids ‐ Pump‐dump‐spectroscopy ‐ Pump‐DFWM ‐ Quantum control spectroscopy Pump-probe: Time-resolved absorption spectroscopy

Transient absorption

• One of the most used time-resolved spectroscopical techniques (third-order method).

I • A (weak) probe pulse measures the variation of absorption after pump  100 I the interaction with a (strong) pump pulse. probe

• Requires spectral resolution, which is given by the detector (filters, gratings, monochromators, etc).

Typical setup

Typical WL Spectrum Pump-probe: Time-resolved absorption spectroscopy

• The absorption of the Probe Intensity is measured at different delays ():

Probe before the pump: no signal!

Delay

S1  I PumpOff  S  log Pr   c  d TA  PumpOn   IPr  S0 Pump-probe: Time-resolved absorption spectroscopy

• The absorption of the Probe Intensity is measured at different delays ():

Delay

S2 Excited State Absorption (ESA) S1  I PumpOff  S  log Pr   c  d TA  PumpOn   IPr  S0 Pump-probe: Time-resolved absorption spectroscopy Example: Energy flow in carotenoids

Pump excites S2, Probe measures population of S1

Signal (Lycopin):

 60

Intensität / mOD 0

0 4 8 12 16 20  / ps Interpretation of signal: Fit to rise and decay of the transient

60 60  = 4.10 0.02 ps Abfall 40 40

 = 130 5 fs 20 20 Anstieg

Intensität / mOD 0 Intensität / mOD 0

048121620 -0,2 0,0 0,2 0,4 0,6 0,8  / ps  / ps

4.1 ps → S1 time constant

130 fs → S2 time constant

Signal at this wavelength probes S1 :  Excited state absorption (ESA) Pump-probe: Time-resolved absorption spectroscopy

Das Bild k ann zurzeit nicht angezeigt werden. Broadband‐probing

Das Bild k ann zurzeit nicht angezeigt werden.

‐carotene

Ground‐State Excited State absorption S1 SN Bleach S0‐S2 Transient absorption: Positive and negative signal contributions

 I PumpOff  S  log Pr   c  d TA  PumpOn   IPr 

P I u mp Pr Off  Pr  Positive signal I Pu m pOn P I u mp Pr Off  Pr  Negative signal Excited State Absorption (ESA) I Pu m pOn Stimulated Groundstate‐ Emission (SE) Bleaching (GB) Transient absorption: Positive and negative signal contributions

 I PumpOff  S  log Pr   c  d TA  PumpOn   IPr 

P I u mp Pr Off  Pr  Positive signal I Pu m pOn P I u mp Pr Off  Pr  Negative signal Excited State Absorption (ESA) I Pu m pOn Stimulated Groundstate‐ Emission (SE) Bleaching (GB) Three contributions in transient absorption Pump Step: Probe Step:

Excited State Absorption (ESA)

Stimulated Emission (SE) Pump Ground state bleach (GB) Pump-probe: Time-resolved absorption spectroscopy Example of Femtobiology: Observation of first step in vision ‐ Isomerization of Rhodopsin

570 nm

530 nm 550 nm S1 570 nm Energy 500 nm t T/T  S0 ‐ 500 nm Potential

11‐cis‐Rhodopsin All‐trans Photoprodukt

Isomerization coordinate Delay time, t/ fs  Photosensivity and high quantum yield due to ultrafast non‐adiabatic isomerization reaction R.W. Schoenlein et al., Science 254 (1991) 412 P. Kukura et al., Science 310 (1990) 1006 Femtochemistry: Observation of ultrafast dynamics in complex molecules

 Due to overlapping resonances of many contributing states more sophisticated optical techniques are needed !!  Multidimensional spectroscopy Multidimensional Time-Resolved Spectroscopy

• Multidimensional techniques opens up new observation windows (new axis in your graph).

• Many approaches:  Tailoring of Optical Pulses (Quantum Control Spectroscopy)  Additional Interactions with Optical Pulses.

• Several spectroscopies: 2D Electronic, DQ2D, 4D, …., Pump-DFWM Ultrafast Molecular Spectroscopy

Outline

I. Intro ‐ Ultrafast Molecular Spectroscopy ‐ Time scale of chemical processes, Overview of methods ‐ Pump‐probe principle ‐ seminal experiments, applications ‐ wavepackets

II. Optical Methods of Pump‐Probe‐Spectroscopy ‐ Transient Absorption: Population dynamics ‐ Examples ‐ Problem of overlapping resonances

III. Multidimensional spectroscopy ‐ Case study: dynamics on Carotenoids ‐ Pump‐dump‐spectroscopy ‐ Pump‐DFWM ‐ Quantum control spectroscopy Going beyond simple pump-probe: Complex excitation + complex probe Carotenoids

from Roche catalogue Carotenoids

-Carotin (11)

OH natural, Zeaxanthin (11) in solution HO

Lycopin (11)

Rhodopin in LH2 O glucoside (11) C6H11O3 Makro15 artificial, -Carotin (15) in solution mini9 -Carotin (9) Ultrafast dynamics in Light Harvesting

Internal conv. Energy transfer

BChl

Qy B850

Carotenoid B800

S2 BChl 0-1 0-0 0-2 Qx B800/ B850

400 450 500 550 600 650 700 750 800 850 900 950 Wavelength, nm Polivka & Sundström, Chem. Rev. (2004) Biological function of carotenoids

Light harvesting Photoprotection  Electronic Energy Transfer: fs-ps Quenching } EET between non-degenerate states  Excess vibronic excitation: fs-ps

Classical 3-level Scheme

BUT, theory predicts other states

between S2-S1! Predicted dark states Conjugation length N 13 12 11 10 9 3A - 22000 g 1B + (S ) u 2 20000 1B - (S* ) u T -1 18000

16000 - Energy, cm 2A (S ) g 1

14000

12000 ground state: 1A - (S ) g 0

0,035 0,040 0,045 0,050 0,055 1/(2N+1)

Theory: Tavan & Schulten, J. Chem. Phys. 85 (1986) 6602 Carotenoids in solution

Three different models for relaxation:

~150 fs

~500 fs

~2‐10 ps

Energy level diagram derived from all‐ T. Polìvka, V. Sundström; Chem. Rev. 2004, 4, 2021 trans‐polyenes with C2h symmetry. T. Polìvka, V. Sundström; Chem. Phys. Lett. 2009, 477, 1 Going beyond simple pump-probe: Complex excitation + complex probe Dynamics in Carotenoids studied with transient absorption

Pump excites S2, Probe measures population of S1

Signal (Lycopin):

 60

Intensität / mOD 0

0 4 8 12 16 20  / ps Transient absorption (Zeaxanthin)

S* S1

S-S 02 hot S vibrational cooling bleach 1 S* (hot S0 ???) cold S1 Pump&Probe: kinetics traces

S 1 S* risetime is the lifetime

of S2 fluorescence!

Two Hypothesis:

1. S* does not rise instantaneously, i.e. it starts

from S2 S* OR

2. S* rises instantaneously,i.e. it doesn´t depend on the

population of S2 Study of dynamics in carotinoids with transient absorption

Two possible models which provide an explanation of additional signal:

•Transient absorption (A) increases

with S2. •Stimulated emission (SE)

decreases with S2 .

•Transient absorption (A) increases instantaneously. • Stimuliert emission (SE) decreases

with S2 ab.

 In both cases the sum of A und SE give rise to the same result! W. Wohlleben; J. Phys. Chem. B 2004, 108, 3320. Going beyond simple pump-probe: Complex excitation + complex probe Pump-deplete-probe spectroscopy

S* ?

S0 delay

Pump ~490nm S0-S2 Deplete 800nm S2 -Sn (T<200fs; Fujii, CPL 369 (2003) 165) Probe S0 bleach, S* and S1 absorption correlation with S2 ? Pump-deplete-probe setup

fs-System nc OPA Pump T 490-550nm 30fs

Deplete Rotating cell tprobe

White light- Probe

generation mOD

460-1000 nm delay, ps

Pump Deplete excited state Probe manipulated absorption spectra Transient absorption (reminder)

S* S1

S-S 02 hot S vibrational cooling bleach 1 S* (hot S0 ???) cold S1 Pump-deplete-probe spectra (lycopene)

Pump - deplete S - probe 40 2 Pump - probe

0 absorption change, mOD change, absorption -20

450 500 550 600

probe wavelength, nm S1 follows S2 population S0-S2 bleach unchanged S* signal independent of S2 population J. Phys. Chem. B 108, 3320 (2004) Confirms assumed IRS mechanism! Study of dynamics in carotinoids with transient absorption

Two possible models which provide an explanation of additional signal:

•Transient absorption (A) increases

with S2. •Stimulated emission (SE)

decreases with S2 .

•Transient absorption (A) increases instantaneously. • Stimuliert emission (SE) decreases

with S2 ab.

 In both cases the sum of A und SE give rise to the same result! W. Wohlleben; J. Phys. Chem. B 2004, 108, 3320. Going beyond simple pump-probe: Complex excitation + complex probe Excitation with several pulses (E-Fields): Nonlinear Interaction

12     3   P0    E   EE   EEE ...

Rayleigh-, Frequency Four-Wave- Mixing Raman- Mixing scattering SHG, DFG,… CARS, DFWM, 3, …

2, 1-2,…

in media with inversion symmetry: (2)=0 first non-linear term in gases and liquids: (3) two conditions important: Conservation of energy and momentum

Wavepackets in Carotene

Transient FFT spectrum

C‐C C=C Excited State Dynamics Investigated by Pump‐DFWM

Weak non‐resonant signal Strong resonant signal Excited State Dynamics Investigated by Pump‐DFWM

J Phys Chem A 111 (2007) 10517 Chem Phys Lett 402 (2005) 283 •Pump and Stokes arrive simultaneously J Phys Chem 100 (1996) 5620 •Transients in τ at different values of T Namboodiri et al Laser Phys 19 (2009) 154 Fujiyoshi et al JPCA 108 (2004) 11165 Oberle et al CPL 241 (1995) 281 Probing vibrational dynamics in real‐time Dynamics of Vibrational Modes

Methyl rocking C‐C stretch

THF 370 cm‐1 C=C stretch

0 C=C 200 stretch S1

s f 400 /

T 600

800 1000 1200 1400 1600 1800 2000 0 200 400 600 800 -1 Wavenumbers / cm J. Phys. Chem. B 115 (2011) 8328 Shift of Vibrational Frequencies

C‐C Stretch C=C Stretch C=C Stretch S1

-1 1540 1150 1790 89  1 fs 1530 1140 1780

1520 90  1 fs 1130 1770 1510 0 200 400 600 800 0 200 400 600 800 0 200 400 600 800 Wavenumbers / cm Wavenumbers T / fs T / fs T / fs

•C=C modes are coupled stronger than C‐C mode. •Intra‐ /intermolecular energy distribution 90 fs. •Absence of evolution for the C‐C mode.

Arch. Biochem. Biophys. 483 (2009) 219. Lycopene’s pump‐ DFWM signal

Experimental T vs.  Scan Simulation

-0,0 0,5 1,0 800 800 Lycopene  = 620 nm det 600 600

/ fs / 400 fs / 400  

200 200

0 200 400 600 0 200 400 600 T / fs T / fs Simulation of the pump‐DFWM signal

•Pump‐DFWM = DFWM on excited state.

•Initial pump: 10% population into S2, 1% population into hot S0.

• Simulation of DFWM signal based on Brownian oscillator model.[1]

•Rate model:

[1]S. Mukamel, Principles of Nonlinear Optical Spectroscopy (Oxford University Press, New York, 1995) Lycopene’s pump‐ DFWM signal

Experimental T vs.  Scan Simulation with real pulse duration

-0,0 0,5 1,0 600 600 Lycopene 500  = 620 nm 500 det

400 400 / fs / fs

 300  300

200 200

0 200 400 600 0 200 400 600 T / fs T / fs Lycopene’s pump‐DFWM signal

Experimental T vs.  Scan Vibrational cooling -0.0 0.5 1.0

800 Lycopene  = 620 nm det 600 / fs

 400

200 Stimulated emission pumping (SEP) DFWM 0 200 400 600 T / fs Carotenoids in solution

Three different models for relaxation:

~150 fs

~500 fs

~2‐10 ps

Energy level diagram derived from all‐ trans‐polyenes with C2h symmetry. T. Polìvka, V. Sundström; Chem. Rev. 2004, 4, 2021. Energy levels

Excited state energies are dependent on conjugation length N

Interesting region: • Crossing between states •Spectral region accessible with fs‐ pulses

P. Tavan and K. Schulten J. Chem. Phys. 1986, 85, 6602. Energy levels

Excited state energies are dependent on conjugation length N

11 10 Interesting region: • Crossing between states •Spectral region accessible with fs‐ pulses

lycopene (N = 11)

OCH3

spheroideneK. Furuichi (N et= 10)al. Chem. Phys. Lett. 2002, 356, 547. Lycopene vs. Spheroidene

-0.0 0.5 1.0

800 800 Lycopene Spheroidene  = 620 nm  = 600 nm det det 600 600

/ fs / fs 400

 400 

200 200

0 200 400 600 0 200 400 600 T / fs T / fs Long living signal in spheroidene at later T and overlaid with strong rapidly decaying component. Spheroidene’s pump‐DFWM signal

Experimental T vs.  Scan Vibrational cooling -0.0 0.5 1.0

800 Spheroidene

det = 600 nm 600

/ fs 400 

- 3Ag 200 SEP DFWM 0 200 400 600 T / fs Spheroidene’s pump‐DFWM signal

Experimental T vs.  Scan

-0.0 0.5 1.0

800 Spheroidene

det = 600 nm 600 Additional ESA

/ fs 400 

- 3Ag 200 SEP DFWM 0 200 400 600 T / fs Summary of pump‐DFWM

Pump‐DFWM in combination with numerical model simulations allows determination of relaxation pathways:

Lycopene (N = 11) Spheroidene (N = 10)

J. Chem. Phys. 139 (2013) 074202 Ann. Rev. Phys.Chem., in print Going beyond simple pump-probe: Complex excitation + complex probe Coherent control of chemical reactions

selectivity ?

Laser field E(t)

calculation for real molecules complicated (if not impossible) experimental realization of predicted E-fields difficult Concept:

R.S. E-field

Judson time [fs] and

Rabitz,

Phys.

Rev.

Lett.

68 (1992)

1500 Science

288

(2000)

824 Shaping of fs‐Laser Pulses

Fourier- Ebene Linse Linse

() Gitter

SLM f f f f SLM 640 Pixel

Reference: A.M. Weiner, Rev. Sci. Instrum. 71 (2000) 1929 Liquid crystal spatial ligt modulator

128 pixel device

 Development of new 640 pixel shaper in cooperation with University of Jena and Jenoptik: Appl. Phys. B 72 (2001) 627 LH2 of Rps. Acidophila ‐ Standard model

Internal conv. Energy transfer

BChl

Qy B850

Carotenoid B800

S2 BChl 0-1 0-0 0-2 Qx B800/ B850

400 450 500 550 600 650 700 750 800 850 900 950 Wavelength, nm Polivka & Sundström, Chem. Rev. (2004) Competing deactivation IC‐EET

probe EET

•Significant loss channel IC • Negligible cross talk IC‐EET •Energy funnel precludes back transfer 64‐parameter optimisation of IC/EET

Convergence curve Optimal pulse FROG trace

258

1,4 256 1,3

254 1,2

252 /ET (relative to TL) to (relative /ET 1,1 C I SHG Wellenlänge, nm

1,0 250 TL 1 0 5 10 15 20 25 30 35

Generation Auto-

korrelation 0 -400 -200 0 200 400 Verzögerung, fs Nature 417 (2002) 533 ChemPhysChem 6 (2005) 850 Reducing the complexity

Donor Acceptor Control of Dyad complex IC/ET ET/IC

Collaboration with AMOLF/Twente PNAS 105 (2008) 7641 Optimal Control Results

Natural Light Harvesting: LH2Artifical Light Harvesting: Dyad Bacteriorhodopsin

Prokhorenko et al, Science 313 (2006) 1257.

Herek et al, Nature 417 (2002) 533. Savolainen et al, PNAS 105 (2008) 7641.

Optimal: NA 110cm‐1(300fs) 230cm‐1(145fs)

Anti‐Optimal: 160cm‐1(210fs) 166cm‐1(200fs) 155cm‐1(215fs)

What is the general QM mechanism behind all these results? Further reduction of complexity Time‐resolved FWM spectroscopy of ground‐state dynamics DFWM signal

‐carotene DFWM Signal DFWM

DFWM scheme 0 1000 2000 3000 1 234 Time delay (fs) FFT spectrum

e 35 1157

t 25

15 1524 1269 FFT Spectrum 10 1004  5 g 0 0 500 1000 1500 2000 Frequency(cm-1) Pulse Spacings

Energy (cm-1) T(fs) 2 T(fs) 3 T(fs) 4 T(fs) 5 T(fs)

1524 21.9 43.8 65.7 87.6 109.5 1157 28.8 57.6 86.4 115.2 144 1004 33.2 66.4 99.6 Control of ground state vibrations Nonlinear Raman spectra

Fourier limited  Modes can be selectively excited

Chem. Phys. Lett. 421 ( 2006) 523

99 fs 144 fs 109 fs Pulse ‐ PulseTrain Pulse Train Train Coherent Control (pulse shaping) Quantum Control = + Spectroscopy (QCS) Spectroscopy

• Modify the excitation to learn more about the dynamics • Several possible „new“ molecular responses

 Disentanglement of complex dynamics and symplifying experiments

Nature 417 (2002) 533 ChemPhysChem 6 (2005) 1 JPPA 125 (2006) 194505 PNAS 105 (2008) 7641 Faraday Discuss. 153 (2011) 213

PCCP 10 (2008) 168 Opt. Lett. 37 (2012) 4239 Quantum Control Spectroscopy

How reliable are How can models be To which extent of pulseTechnology shaping refinedConcepts with controlled complexitySystems can capabilities ? dynamics ? coherent control go ?

•Open‐loop complex • Plurality of closed‐/ •Prototype molecul.: pulse synthesis and open‐loop control and Dimers, Dyes etc. characterization pump‐probe • Biomolecules: •UVTechnology‐MIR shaping • ParameterisationConcepts of ultrafastSystems energy flow • Photonic crystalls pulse shapes in LH2 and •FWM‐spectroscopy •Role of coherence carotenoids and contrability • Nonlinear microscopy •Medical application Literature

Basics and Applications: • Ultrashort Laser Pulse Phenomena, J.‐C. Diels and W. Rudolph, 2nd ed., Academic Press, 2006 • Femtosecond Laser Pulses, ed. by C. Rullière, 2nd ed., Springer, 2005 • Laser Spectroscopy: Vol. 1 and 2, W. Demtröder, 4th ed., Springer, 2008

Femtochemistry: • Femtochemistry: Atomic‐scale dynamics of the chemical bond, A.H. Zewail, J. Phys. Chem. A,Vol. 104, pp. 5660‐5694, 2000 • Ultrafast Phenomena I ‐ XVII, Conference Proceedings, Springer and Oxford Press • Femtochemistry and Femtobiology, 1994 – 2011, Proceedings, Elsevier et al. • Femtosecond Laser Spectroscopy, ed. by P. Hannaford, Springer, 2005

Control: • Coherence and Control in Chemistry, Faraday Discuss., 2011, 153, RSC Publishing • Quantum Control of Molecular Processes, P. Brumer and M. Shapiro, 2nd ed., 2011, Wiley‐VCH Verlag • Optical Control of Molecular Dynamics, S.A. Rice and M. Zhao, 2000, John Wiley & Sons Femtoscience: Ultrafast Dynamics, Spectroscopy and Coherent Control Thanks to … •Tiago Buckup Marburg•H.‐R. Volpp •Prof.•Jan Norbert‐Philip Kraack Hampp Marburg Financial Support • Marie Marek •Prof. Norbert Hampp Munich Max‐Planck‐Gesellschaft •Jens Möhring Munich •Prof. Regina de Vivie‐Riedle BMBF: ActIOL + MediCARS • Christoph Pohling •Prof. Regina de Vivie‐Riedle EU: CROSSTRAP • Judith•Jean Voll Rehbinder • Judith Voll Fonds der Chemischen Industrie Twente,• Dzmitry NL Starukhin Twente, NL •Prof.• Alexander Jennifer Wipfler Herek •Prof. Jennifer Herek •Jürgen Hauer • Bernhard von Vacano Financial Support

Max‐Planck‐Gesellschaft BMBF: ActIOL + MediCARS EU: CROSSTRAP Fonds der Chemischen Industrie …the audience!