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SKKU-EMBO conferenceJUNE 25, 2016
Minhaeng ChoIBS Center for Molecular Spectroscopy and Dynamics (CMSD),
Department of Chemistry, Korea University
APPLICATIONS OF COHERENT
MULTIDIMENSIONAL SPECTROSCOPY
SCIENTIFIC REVOLUTION & PARADIGM SHIFT
Scientific Developments
Theoretical Experimental
Newton’s Mechanics
Quantum Mechanics
The theory of evolution
X-ray diffraction
Nuclear magnetic
resonance (NMR)
LASER (MASER)
Novel concepts
Different and generalized
viewpoints
Novel tools
Observations of
the unseen
Freeman Dyson
(1923 ~)
Physicist
Inst. for Advanced
Study (IAS,Princeton)A Novel Experimental Tool!
Multi-dimensional optical and
chiral spectroscopy
SPECTROSCOPY
Electromagnetic Wave Amplitude (Intensity), Frequency, and Phase
Field-Matter Interaction-Induced Changes in EMW Properties
Structure and Dynamics of Complex Molecular Systems
“SEEING IS BELIEVING”
Eadweard Muybridge (1887)
“The movements of participants in molecular dramas can be recorded
in vivid detail, using coherent multidimensional spectroscopy”
ULTIMATE GOAL
Spectroscopy for “MOLECULAR MOTION PICTURE”
Femtosecond (10-15 s) multidimensional
vibrational/electronic spectroscopy
TWO TECHNICAL DIFFICULTIES!
ULTRASMALL (10-10 m)
AND(!)
ULTRAFAST (10-15 s)
HOW TO OVERCOME
ULTRAHIGH SPATIAL RESOLUTION
AND(!)
ULTRAFAST TIME-RESOLUTION
Researchers use a variety of tools to probe
protein function and interactions, with drug
discovery the major goal
One of seven research fields in 21C
“Large-scale protein folding and 3-D
structure studies”
X-ray
crystallo-
graphy
2D-NMR
Advantages Restrictions
High spatial
(atomic)
resolution
Solution
sample
Molecular
crystal &
Low time-
resolution
Low time-
resolution
Protein Structure Determination: Conventional Tools
Advantage and Limitation
Cho and coworkers, Phys Chem Chem Phys
(review) 10, 3839 (2008)
2D CP-PE spectrum of FMO light-harvesting
protein complexOLD PARADIGM: STRUCTURE
NEW PARADIGM: DYNAMICS
Femtosecond 2-Dimensional Vibrational/Electronic Spectroscopy
Brief historical accountsNonlinear optical spectroscopy: Long history since Bloembergen, Shen,…
4WM: Ippen, Shank, Fleming, Wiersma, Warren, Albrecht, Mukamel, Skinner, Cho, etc.
In 1981, Warren, W. S.; Zewail, A. H., Optical analogs of NMR phase coherent multiple pulse spectroscopy,
J. Chem. Phys. 75, 5956–5958 (1981). 2D optical spectroscopy alluded but unsuccessful (long (>ps) pulse)
1. Fifth-order nonlinear optical spectroscopy (two (elec. or vib.) coherence evolutions)
Fifth-order electronic spectroscopy: Cho & Fleming, J. Phys. Chem. (1994)
Fifth-order Raman (vibrational) spectroscopy: Tanimura & Mukamel, J. Chem. Phys. (1993)
Complicated due to undesired contributions and weak signals. Not successful
2. Electronic (vis) (photon echo) four-wave mixing spectroscopy
Spectral interferometry of photon echo: Jonas, Chem. Phys. Lett (1998)
2D elec. spectroscopy of photo-synthetic complex: Cho, Fleming et al, Nature (2005)
3. 2D IR-vis four-wave-mixing spectroscopy (vibrational + electronic)
2D IR-IR-vis spectroscopy: Cho, J. Chem. Phys. (1998) (theoretical)
DOVE-IR: Wright, J. Am. Chem. Soc. (1999) (experimental)
4. IR four-wave mixing spectroscopy (Vibrational)
IR photon echo: Fayer & coworkers (1993) etc. (using a free electron laser)
2D IR pump-probe: Hamm, Lim, & Hochstrasser, J. Phys. Chem. (1998)
Experiments: Hochstrasser, Hamm, Tokmakoff, Zanni, etc.
Theory: Cho, Mukamel, Skinner, Jansen, Knoester, Stock,etc.
Cho, Two-dimensional optical spectroscopy, CRC press (2009)
Q1-mode Q2-mode
Vibrational
energy
relaxation
(dissipation)
Vibrational
phase
relaxation
(dephasing)
Vibrational
coupling
C O H N
Q1 Q2
C
O
N
H
CH
CH3
C
O
N
H
C C
H H Nuclear spin 2Nuclear spin 1
J
J
COSY-NMR NOESY-NMR Connectivity between different atoms
Coherent 2D vib. Spectroscopy Connectivity between
different vibrational chromophores (groups)
2D
NM
R2D
Vib
. Spec.
2D NMR & 2D Vibrational Spectroscopy
Vibrational coupling versus Spin-spin coupling
M. Cho, “Coherent 2D Optical Spectroscopy” Chem. Rev. (2008)
M. Cho, “Two-Dimensional Vibrational Spectroscopy”, in Adv. Multi-photon Processes
and Spectroscopy, vol.12, page 229 (1999) (Review Article)
Why coherent multidimensional
(IR, Raman, electronic, IR-vis, etc.) spectroscopy?
M. Cho, “Coherent 2D Optical Spectroscopy” Chem. Rev. (2008)
1.TIME RESOLUTION~10-15 (2D optical spect.) vs ~10-6 (2D NMR)
2. NUMBER OF OBSERVABLES (PEAKS)~ N (1D)
~ N2 (2D)
~ Nd (d-dimensional spectroscopy)
3. THE SMALL IS CRUCIAL!
OBSERVABLES & INFORMATION2D OPTICAL (VIB./ELEC.) SPECTROSCOPY
1. Measurements of angles() between two different
transition (electric and/or magnetic) dipoles
(Chiral or achiral) Molecular Structure
2. Measurements of frequency random jumps between
discrete states induced by chemical exchange processes
Chemical Kinetics
3. Measurements of population or coherence transfers
by electronic couplings
State-to-state quantum transition & connectivity
M. Cho, Two-Dimensional Optical Spectroscopy, CRC press (Taylor&Francis), 2009
Definition of density operator
Quantum mechanical Liouville equation
Hamiltonian consisting of zero-order (mol.+rad.) and perturbation (rad.-mol. interaction) term
Time-evolution operator in Liouville space (time-dependent perturbation theory)
Third-order polarization induced by nonlinear (3rd-order) radiation-matter interactions
TIME-DOMAIN NONLINEAR SPECTROSCOPY:
Theoretical Consideration( ) | ( ) ( ) |t t t
ˆ( ) [ ( ), ( )] ( ) ( )i i
t H t t L t tt
0ˆ ˆ ˆ( ) ( ) ( )IH t H t H t
00( , ) exp ( )
t
t
iV t t d L
+=|m><n| |m><n| |m><n| = |m><n| - |m><n|
+=
+= + +
+= + + + + + +
(t0)P(3)(t) = < >NM. Cho, Two-Dimensional Optical Spectroscopy (CRC, 2009)
Signal
field ELO
Esig+ELO
Sample
js
XY
Z
T
j1
j2
j3
k2
k3
k1
k2 k3k1 LO Half-wave Plate
PolarizerBeam SplitterMirror
tr
MCT Array
Detectorfs IR
pulse
S
Polarization-Angle-Scanning 2D Spectroscopy
τ T t
i t
t
e
ω
g
e t e i t
t e tωg e
g
e
ρ t ABSORPTION
FREQUENCY
EMISSION
FREQUENCY
t
SIGNAL
Recovered
from Experiment
3( , , )S T t
Time
Coherent 2D Optical SpectroscopySpectral interferometry for heterodyne-detection
τ T t
i t
t
e
ω
g
e t e i t
t e tωg e
g
e
ρ t Excitation
Frequency
Emission
Frequency
t
SIGNAL
Recovered
from Experiment
3( , , )S T t
Time
Coherent 2D Optical SpectroscopySpectral interferometry for heterodyne-detection
t g
Shutter Speed Exposure Time
Time-resolved two-dimensional spectroscopy is useful to
measure correlation between two observables, e.g., transition
frequencies, separated in time, which in turn provide
information on spatial connectivity between chromophores, i.e.,
structure, and coupling. ; t0 tT, t ; t0
2D ELECTRONIC SPECTROSCOPY
Two coupled oscillators (Q1 & Q2)
FT2
2 1 1 1( ) ( ) ( ) (0)t t t t
2D SPECTROSCOPY
21
1 2( , ; )I Time
t1t2
2-D spectrum
Jeon et al, Acc. Chem. Res. (2009)
COUPLING CROSS PEAKS!?
Negatively
Correlated
Spectral
MotionPositively
Correlated
Spectral
Motion0j k
0j k
FMO (Fenna-Matthews-Olson) Photosynthetic Complex (CMC2)
1
2
3
4
56
7
1234567
ExcitonLevel
Allen and coworkers
J. Mol. Biol. (1997)
271, 456±471
A model of the position of the cofactors of the BChl a
protein and reaction center in the cell membrane.
Diagonal peaks
GB+SE with Gjj(T)
QUANTUM INTERFERENCE
Off-diagonal peaks
GB
Off-diagonal peaks
SE with Gjk(T)
Off-diagonal
peaks
EA with
Gjj(T)
Off-diagonal
peaks
EA with
Gjk(T)
Total spectrum
at T=1000 fs
(+)
(+)
(+)
(-)
(-)
(d)
(e)
(f)
(a)
(b)
(c)
(cm-1) (cm-1)
Diagonal peaks
GB+SE with Gjj(T)
QUANTUM INTERFERENCE
Off-diagonal peaks
GB
Off-diagonal peaks
SE with Gjk(T)
Off-diagonal
peaks
EA with
Gjj(T)
Off-diagonal
peaks
EA with
Gjk(T)
Total spectrum
at T=1000 fs
(+)
(+)
(+)
(-)
(-)
(d)
(e)
(f)
(a)
(b)
(c)
(cm-1) (cm-1)
Numerically simulated 2D spectra
t
(cm-1) (cm-1)
Two-dimensional spectroscopy
of electronic couplings in
photosynthesis
100 fs < Waiting Time (T) < 2000 fs
Time
100 fs
200 fs
300 fs
600 fs
1000 fs
COUPLINGS Ex. TRANSFER
Nature 434, 625 (2005)
WHAT DID WE LEARN FROM 2D ELECTRONIC SPECTROSCOPY OF
FMO LIGHT-HARVESTING COMPLEX?
1. Demonstration of how electronic couplings within molecular complexes can be made
visible directly by measuring 2D femtosecond photon-echo spectra
(Amplitudes of cross peaks)
2. Development of a self-consistent theory for nonlinear spectroscopy and excitation
transport
(Energy transport through space with tens of nanometer spatial resolution and
femtosecond temporal resolution)
3. Mechanism of energy relaxation processes in FMO photosynthetic complex
STRUCTURE AND DYNAMICS
2D vibrational or electronic spectroscopy
C
O
N
H
CH3H3C
H
O
Me
O
H Me
C
O
N
H
CH3H3C
H
O
Me
H
O
Me
O
H Me
CH3-CN
CHCl3
+ −
+ −
Ion pairing dynamicsubiquitin FMO complex
hairpin
-sheet polypeptides
Hahn et al., J. Chem. Phys. 123, 84905 (2005)
Anti-parallel and prallel -sheets: spectroscopically distinguishable?
Hahn, et al. J. Chem. Phys.
123, 84905 (2005)
1620 1660 1700
1620
1660
1700
1620 1660 1700-0.02
0
0.02
1/2c(cm
-1)
3/2c(c
m-1)
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
Antiparallel -Sheet
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
C
O
N
H
Parallel -Sheet
2 2 2sinkj k j jkS
2D Difference
Spectrum
ZZZZ-3ZXXZ
Cross peak
intensity
Amyloid Aggregate
Structure?
Middleton et al. Nature Chem. (2012)
M. Cho, Nature Chem. 4, 339 (2012)
Various DNA double helical structures
Spectroscopic probing of BZ or BA transitions in real time?
(a) A-DNA : (GC)3 (b) B-DNA : (GC)3 (c) A-DNA : (GC)4
2.9Å 3.4Å4.1Å
3.5Å
A-DNA B-DNA Z-DNA
Lee et al. J. Chem. Phys. 126, 145102 (2007)
1D and 2D IR spectra of (GC)n(numerical simulation results)
(a)
ωt
(b)
ωt
(c)
ωτ
ωt
A-DNA B-DNA Z-DNA
1. C. Lee et al. J. Chem. Phys. 125, 114508 (2006)
2. C. Lee et al. J. Chem. Phys. 125, 114509 (2006)
3. C. Lee et al. J. Chem. Phys. 125, 114510 (2006)
4. C. Lee et al. J. Chem. Phys. 126, 145102 (2007)
IR PROBE + time-RESOLVED IR SPECTROSCOPY
Linear (Chiroptical) SpectroscopyElectric Field Approach
HANDEDNESS IN NATURE
Molecular Chirality in Motion
CHIRAL AMINO ACIDS:
Building blocks of proteins
Myoglobin
NTL-9
Met1Aha
NTL-9
Ile4Aha
BIOMOLECULES ARE INTRINSICALLY CHIRAL
Chiral molecules: Optical activityA chiral molecule is a type of molecule that lacks an internal plane of
symmetry and thus has a non-superimposable mirror image.
FMO Complex
PROTEINS OF INTEREST
Optical Rotation
j
Optical rotatory dispersion (ORD) measurement
Linear
Polarizer
Chiral
Sample
Detector
A brief historical account on optical rotation1. 1811. F. J. D. Arago (French physicist). Optical Rotation (OR) in quartz
2. 1811. J. B. Biot. OR in liquids (turpentine, an organic substance)
3. 1822. J. F. W. Herschel (English astronomer). OR in two forms of quartz
4. 1822~. Polarimeter for OR measurement, e.g., glucose concentration
5. 1849. Louis Pasteur. OR measurements of two forms of tartaric acid crystals.
two different structures (optical isomers!)
6. 1874. J. H. van’t Hoff and J. A. Le Bel. Chemical bonds between C-atom and
neighbors tetrahedral structure
three-dimensional nature of molecules
Analyzer
( )j
frequency-dependent
optical rotation
OR
DC
DO
RD
+ C
D
ORD measures difference in birefringence for LCP and RCP fields passing
through chiral medium
CD measures difference in absorption of LCP and RCP fields by chiral molecules
Optical activity of chiral molecular systems refers to both ORD and CD, which are related to each other via
Kramers-Kronig relation.
INCIDENT TRANSMITTED
nLCP ≠ nRCP
κLCP ≠ κRCP
femtosecond Linear Chiroptical Activity Measurement
Chiral spectroscopy
Conventional approach: Differential absorption measurement
using left- and right-handed helical (Left- and Right-CP) E-fields
In 2005, I had a series of questions that are….
Background noise problem
A/A ~ 10-3 – 10-6
Q) Is it always necessary to use chiral (left- or right-handed) fields to characterize molecular chirality? (Traditional Approach based on Intensity Mesurement)
A) Not necessarily
Q) Then, how is it possible to characterize certain handed molecule with non-chiral field?
A) Spectrometer or detection scheme should be chiral! (New Approach based on Phase-Amplitude Measurement)
Q) Can a femtosecond linearly polarized pulse (non-chiral field) be
used to determine molecular chirality?
A) Yes!
Vertical LP (VLP)
Horizontal LP (HLP)
Transverse EM wave: Two linear polarization states of
electric field (E-field)
VLP and HLP of the transverse E-field propagating in a vacuum or
an isotropic medium with achiral molecules are UNCOUPLED!
(from Maxwell equation)
e.g., VLP into a glass of water, VLP out with zero HLP
Q) What happens when VLP passes through a sugar solution?
VLPin |HLPout|2/|VLPout|
2 = 10-4
k
HLPout is generated by the radiation-matter interaction of chiral
molecules with VLPin.
VLP and HLP become COUPLED! (from Maxwell equation)
(A Cause-and-Effect phenomenon)
What are the cause and the effect in this case?
Cause: Magnetic field-magnetic dipole interaction
Effect: Electric field-electric dipole interaction-induced E-field
What is the connection (linear response) function?
Chiral Solution
E(t)
B(t)
How to separately measure HLP (E) and VLP(EII)
electric fields?
After solving the coupled Maxwell equation, which is
2 22
2 2 2 2
1 4( , ) ( , ) ( , )z t z t z t
c t c t
E E P
2 22
||2 2 2 2
0 0
1 4( , ) ( , ) ( ) ( , ) ( ) ( , )
2 2
t t
xx xx
m
iN NE z t E z t d t E z d t E z
c t c t V V
( , )E z tFor , we have a coupled differential equation:
Rhee et al. J. Chem. Phys (2008)
Determination of absolute CD and ORD values
CHIRAL susceptibility is a complex function, and
( ) ( ) ( )L R
' "( ) ( )i
circular
birefringence
(CB)
'2( ) ( )
( )n
n
''4( ) ( )
( )a
n c
circular
birefringence
(ORD)
differential
absorption
coefficient
(CD)
circular
dichroism
(CD)
||
( ))
( )(
E
E
THEN, HOW TO MEASURE COMPLEX
ELECTRIC FIELD SPECTRUM?
1. Electric field amplitude E versus intensity |E|2
2. QM Wavefunction versus probability ||2
PHASE, PHASE, PHASE!
Experimental setup: Single-Shot Electronic CD/ORD
Ultimate sensitivity: Single pulse measurement!
For the success of ultrasensitive measurements
(1) Quasi-null (perpendicular polarizer) geometry
(2) Heterodyne detection
(3) Self-referencing technique
Phase and Amplitude Measurements
Mach-Zehnder Interferometry
What are experimentally measured?
Spectral interferogram (interference signal between signal E and reference E
and ( )S || ( )S
Rhee et al, Nature (2009), JOSA (2009), ChemPhysChem (2010)
WHAT IS THE UNDERLYING PRINCIPLE?
( )E || ( )E and
Well-known transformation
THOMAS YOUNG’S EXPERIMENT
MODIFICATION OF YOUNG’S DOUBLE-SLIT EXPERIMENT!
What if a chiral molecule is placed at one of the two slits?
||
( ))
( )(
E
E
Molecular Chirality versus Optical Chirality
Molecular Chirality, Optical Activity and Rotatory Strength
Im( )μ mR
Q) What is the corresponding (chiral) property of electromagnetic field?
Optical Chirality (initially considered by Lipkin (1960’s) as one of Zilches
0
0
1( ) ( )
2 2E E B BC
0
2B E E B
*0 Im2
E B
*4Im( ) ImA A A μ m E B
Q) What is the difference in the rates of absorption with (+) and
(-)-handed electromagnetic fields?
Single-shot Electronic Optical Activity Interferometry
DNA-templated helical cyanine dye assembly
1
2
3
4
Face-to-Face Dimer
Tetramer1
2
3
4
ips = 3.6 Å
shift = 2.4 Å
dist = 18.5 Å
Induced Optical Activity of DNA-Templated Cyanine Dye Aggregates: Exciton Coupling Theory and TD-DFT Studies
Classical MD simulation
Initial Structure: NUCGEN routine in AMBER
Force Field: ff09 + TIP3P (300K)
Equilibration: 5 ns NVT Simulation: 20 ns NPT
QM calculation
Induced Optical Activity of DNA-Templated Cyanine Dye Aggregates
1. TD-DFT Calculation Results
TD-DFT
Functional (nm) (nm) (nm)
B3LYP 478 (-3214) 506 (4856) - 29
CAM-B3LYP 458 (-4054) 490 (4011) 517 (564) 32
PBE0 469 (-3588) 497 (4820) - 28
LC-ωPBEh 451 (-2702) 484 (4071) - 33
M05-2X 458 (-4325) 481 (4232) 520 (608) 23
M06-2X 467 (-3453) 490 (5153) 532 (510) 24
Experimental 588 607 ~670 19
1
1
2
(tetramer)
2. Exciton coupling theory
1
ˆ ˆ ˆN
l
l
H H V
1 21 2
12
ˆ ˆ( ) ( )1ˆ2
N Nl m
l m l
V d dr
r r
r r
(1 ) (1 , )lm lm l lm lmH E V l m N
Electronic coupling constant
1 21 2
12
( ) ( )eg ge
l mlmV d d
r
r rr r
HOMO LUMO
1
2
3
4
V13 = V24: Face-to-Face Coupling
Coupling constants (cm-1): TDC, TrESP and FED methods
Basis sets used: 6-311++G(2df,2pd) (6-31+G(d,p))
Wavelength (nm)
500 550 600 650 700
CD
(M
ea
sure
d )
600
300
0
- 300
- 600
6000
3000
0
- 3000
- 6000
CD
(Calc
ula
ted )
400 450 500 550
Experimental
TDDFT/CAM-B3LYP
Frenkel Exciton x3
200
0
OR
D (
Measure
d )
- 400
- 200
Wavelength (nm)
500 550 600 650 700
400 450 500 550
2000
0
- 4000
- 2000
OR
D (C
alc
ula
ted )
Experimental
TDDFT/CAM-B3LYP
Frenkel Exciton x3
23000
22000
21000
20000
19000
18000
17000
16000
15000
0
H1 → L1
H1‒H3 → L1‒L3
450
550
600
500
650
H → L
H1‒H3 → L1+L3
H1 → L1
H1+H3 → L1‒L3
H3 → L3
H3 → L3
H2+H4 → L2‒L4
H2+H4 → L2+L4
Monomer Dimer Tetramer
H2‒H4 → L2‒L4
H1‒H3 → L1+L3
H2‒H4 → L2+L4
2
0
0
ˆIm 0 0( )
V
K
K
eR K K m
E E m
Numerical Simulations:
CD and ORD spectra
2 20 0
2 20 0
( ) ( )
2 20 00
0 0 0
( ) ( ) ( )
2erfc erfc
3 2 2
K K
K K
L R
K KK
K K K K
iR e i e i
NANOSCALE METAMATERIAL-ASSISTED
CHIROPTICAL SPECTROSCOPY
Globally Enhanced Chiral Field
Generation by Negative-Index
Metamaterials
Yoo et al., Phys. Rev. B 89, 161505 (2014)
*0 Im2
C
E B2
0 0 /CPLC E c
Double Fishnet Negative-Index Metamaterial
/ CPLC C
Distributions of Elec. And Mag. Fields, and
Enhancement Factor
Top view
Side view
1s
tm
ag
neti
c r
eso
nan
ce
at
892 n
m
2n
dm
ag
ne
tic r
eso
nan
ce
at
682 n
m
Top view
Side view
Enhancement Factor
Volume-Averaged Optical Chirality: Size-dependence
Yoo et al., Phys. Rev. B 89, 161505 (2014)
Non-chiral negative-index metamaterials
can be used to generate the enhanced
chiral fields via simultaneous excitation
of electric and magnetic fields in the
longitudinal direction.
Useful chiroptical spectroscopy
The bridging of chiroptical spectroscopy
and photonic metamaterials, two distinct
disciplines of optics, will offer new
possibilities for applications of negative-
index metamaterials in the future.
WHAT IS NEXT?
Optical Activity (Chiroptical) Spectroscopy (Sensitive to Molecular Chirality)
+
Multi-Dimensional Optical Spectroscopy(Enhanced Spectral and Time Resolution)
Multi-Dimensional Chiroptical Spectroscopy2D Circular Dichroism?
2D Optical Rotatory Dispersion?
2D Raman Optical Activity?
Circularly polarized photon echo
Nonlinear optical activity (CD or ORD) spectroscopy
τ T t SIGNAL
Time
Conventional (linearly polarized) photon echo
R
L Z
Z Z Z Z
Z Z
SZZZZ
SLZZZ
Z Z Z SRZZZ
S=SLZZZ-SRZZZ
12000 12300 12600
CD
spectr
a
Frequency (cm-1)
Experiment
7
6
5
4
3
2
1
76
5
4
3
2
1
Absorp
tion
6 K
77 K
1
2
3
4
56
7
1234567
Exciton Level
Fenna-Matthews-Olson
LH protein complex
12000 12350 12700 1 ( )cm
2D photon echo
spectrum of FMO light-
harvesting complex
(Experimentally Measured)
Absorption
Abso
rpti
on
t
Tw = 1 ps
12000 12350 12700 1 ( )cm
t
A
B
2D Circularly polarized
photon echo
spectrum (No experiment yet)
Abso
rpti
on
Circular dichroism
Choi et al. PCCP (2008)Cho et al. J. Phys. Chem. B (2005)
and Nature 434, 625(2005)
Cho, Two-dimensional optical spectroscopy, CRC press (2009)
Circularly Polarized
Sum-Frequency-
Generation
J. Chem. Phys.
116, 1562 (2002)
2D Circularly Polarized
Pump-Probe (2D CP-PP)
(Nonlinear CD and ORD)
J. Chem. Phys.
119, 7003 (2003)
2D Circularly Polarized
Photon Echo (JCP 2006
& PCCP 2008)
2D Sum-Frequency-
Generation
Spectroscopy (Chem
Phys 2008)
etc…
Theoretical
Nanosecond temperature-jump with an intense IR pulse initiates non-equilibrium relaxation of biomolecules (unfolding/folding), which is
monitored by using 2DIR or femtosecond CD (ORD) spectroscopic method
Excitation of OD stretch
overtone band of D2O
= 2.0 m (D2O)
→ fast energy dissipation
→ local heating
TEMPERATURE-JUMP 2DIR OR fs-CD PROBE
Probing conformational transition of proteins
HOW TO (T-JUMP)?
TEAM MEMBERS, COLLABORATORS, & ACKNOWLEDGMENTS
RESEARCH FELLOWS
Dr. Jun-Ho Choi
Dr. Jonggu Jeon
Dr. Hochan Lee
Dr. Kwang-Hee Park
Dr. Pramod K. Verma
Dr. Aude Lietard
Dr. Achintya Kundu
Dr. Cho-Shuen Hsieh
Dr. Sreedar Sunku
Former postdoc. and grad. students:
Dr. I.-T. Eom (Pohang), Dr. S. Kim (Pohang), Joseph Choi (U.Roch.)
COLLABORATORS
Hogyu Han(Korea U), Hanju Rhee(KBSI), G. R. Fleming(Berkeley),
G. Scholes(Toronto), Y. Tanimura (Kyoto), I. Ohmine (IMS), S. Saito(IMS)
A. Tokmakoff (MIT), J. C. Wright (Wisconsin), S. Mukamel (UC-Irvine),
G. D. Rose (Johns Hopkins U.), M. D. Fayer (Stanford U.),
N. Kallenbach(NYU), J. Howell (Rochester U.), L. Barron (Glasgow)
and so on.
FUNDS: INSTITUTE FOR BASIC SCIENCE (IBS), KOREA
GRADUATE STUDENTS
Joo-Yong Lee Michal Maj
Bartosz Blasiak Joon-Hyung Lim
So-Hee Lim Hyung-Ran Choi
D. Kossowska E-Hyun Lee
Jun-Young Park Do-Yeon Kim
Min-Seok Kim
Thank you
