Eadweard Muybridge (1887) U LTIMATE G OAL Spectroscopy for M - PowerPoint PPT Presentation

A PPLICATIONS OF C OHERENT M ULTIDIMENSIONAL S PECTROSCOPY SKKU-EMBO conference JUNE 25, 2016 Minhaeng Cho IBS Center for Molecular Spectroscopy and Dynamics (CMSD), Department of Chemistry, Korea University

S CIENTIFIC R EVOLUTION & P ARADIGM S HIFT Scientific Developments Theoretical Experimental  Newton’s Mechanics  X-ray diffraction  Quantum Mechanics  Nuclear magnetic  The theory of evolution resonance (NMR)  LASER (MASER)  Novel concepts  Novel tools  Freeman Dyson  Different and generalized  Observations of (1923 ~) Physicist viewpoints the unseen Inst. for Advanced Study (IAS,Princeton) A Novel Experimental Tool! Multi-dimensional optical and chiral spectroscopy

“ S EEING IS B ELIEVING” S PECTROSCOPY Electromagnetic Wave Amplitude (Intensity), Frequency, and Phase Field-Matter Interaction-Induced Changes in EMW Properties Structure and Dynamics of Complex Molecular Systems

Eadweard Muybridge (1887)

U LTIMATE G OAL Spectroscopy for “ M OLECULAR M OTION P ICTURE” Femtosecond (10 -15 s) multidimensional vibrational/electronic spectroscopy “The movements of participants in molecular dramas can be recorded in vivid detail, using coherent multidimensional spectroscopy”

T WO T ECHNICAL D IFFICULTIES! ULTRASMALL (10 -10 m) AND(!) ULTRAFAST (10 -15 s) H OW TO OVERCOME ULTRAHIGH SPATIAL RESOLUTION AND(!) ULTRAFAST TIME-RESOLUTION

Protein Structure Determination: Conventional Tools Advantage and Limitation  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 ” Advantages Restrictions Molecular High spatial X-ray crystal & (atomic) crystallo- Low time- resolution graphy resolution Solution Low time- 2D-NMR sample resolution OLD PARADIGM: STRUCTURE 2D CP-PE spectrum of FMO light-harvesting protein complex Cho and coworkers, Phys Chem Chem Phys NEW PARADIGM: DYNAMICS (review) 10, 3839 (2008)

Femtosecond 2-Dimensional Vibrational/Electronic Spectroscopy

Brief historical accounts Nonlinear 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)

2D NMR & 2D Vibrational Spectroscopy Vibrational coupling versus Spin-spin coupling 2D Vib. Spec. Q 1 -mode Q 2 -mode Q 2 Q 1 Vibrational C O H N Vibrational energy phase Vibrational relaxation relaxation coupling J (dissipation) (dephasing) J O C  H 3 H 2D NMR Nuclear spin 1 Nuclear spin 2 H C C  H N H N C C C H O COSY-NMR NOESY-NMR Connectivity between different atoms Coherent 2D vib. Spectroscopy Connectivity between different vibrational chromophores (groups) M. Cho, “ Two-Dimensional Vibrational Spectroscopy ”, in Adv. Multi -photon Processes and Spectroscopy, vol.12, page 229 (1999) (Review Article) M. Cho, “ Coherent 2D Optical Spectroscopy ” Chem. Rev. (2008)

Why coherent multidimensional (IR, Raman, electronic, IR-vis, etc.) spectroscopy? 1.TIME RESOLUTION ~10 -15 (2D optical spect.) vs ~10 -6 (2D NMR) 2. NUMBER OF OBSERVABLES (PEAKS) ~ N (1D) ~ N 2 (2D) ~ N d (d-dimensional spectroscopy) 3. THE SMALL IS CRUCIAL! M. Cho, “ Coherent 2D Optical Spectroscopy ” Chem. Rev. (2008)

OBSERVABLES & INFORMATION 2D 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

TIME-DOMAIN NONLINEAR SPECTROSCOPY: Theoretical Consideration      Definition of density operator ( ) | t ( ) t ( ) | t  i i ˆ t        Quantum mechanical Liouville equation ( ) [ ( ), ( )] ( ) ( ) t H t t L t t  Hamiltonian consisting of zero-order (mol.+rad.) and perturbation (rad.-mol. interaction) term ˆ ˆ ˆ   H t ( ) H t ( ) H ( ) t 0 I Time-evolution operator in Liouville space (time-dependent perturbation theory)   i  t      ( , ) exp  ( )  V t t d L  0   t 0 = + - | m >< n | | m >< n | | m >< n | | m >< n | + | m >< n | = = + + = + + + + + + + + = Third-order polarization induced by nonlinear (3 rd -order) radiation-matter interactions  ( t 0 )  ˆ P (3) ( t ) = < > N M. Cho, Two-Dimensional Optical Spectroscopy (CRC, 2009)

Polarization-Angle-Scanning 2D Spectroscopy E sig +E LO j s  T Signal j 1 field E LO k 1 j 2 k 2 Sample Z j 3 k 3 X Y Half-wave Plate k 1 k 2 k 3 tr LO Polarizer Beam Splitter Mirror MCT Array Detector fs IR pulse S

Coherent 2D Optical Spectroscopy Spectral interferometry for heterodyne-detection τ t T SIGNAL Time     t g       e       ω i t t t e g e t     ω i t  e e e g   ABSORPTION EMISSION ρ t FREQUENCY FREQUENCY    t 3 ( , , )    S T t Recovered from Experiment

Coherent 2D Optical Spectroscopy Spectral interferometry for heterodyne-detection Shutter Speed Exposure Time τ t T SIGNAL Time     t g       e       ω i t t t e g e t Time-resolved two-dimensional spectroscopy is useful to     ω i t  e e e measure correlation between two observables, e.g., transition     frequencies, separated in t time, g which in turn provide g information on spatial connectivity between chromophores, i.e.,   Excitation      ; t 0   t  T , t ; t 0  Emission ρ t structure, and coupling. Frequency Frequency    t 3 ( , , )    S T t Recovered from Experiment

2D ELECTRONIC SPECTROSCOPY

2D SPECTROSCOPY Two coupled oscillators (Q 1 & Q 2 ) 2-D spectrum      ( ) ( ) ( ) (0) t t t t I   Time 2 1 1 1 ( , ; ) 1 2 FT 2  2 t 2 t 1  1 COUPLING CROSS PEAKS!? Jeon et al, Acc. Chem. Res. (2009)

Negatively Correlated Spectral Positively Motion Correlated    Spectral 0 j k Motion    0 j k

FMO (Fenna-Matthews-Olson) Photosynthetic Complex (CMC2) A model of the position of the cofactors of the BChl a protein and reaction center in the cell membrane . Allen and coworkers J. Mol. Biol. (1997) Exciton 271, 456 ± 471 Level 1 2 3 3 4 5 6 7 2 4 7 1 5 6

QUANTUM INTERFERENCE QUANTUM INTERFERENCE (a) (a) (d) (d) Off-diagonal peaks Off-diagonal peaks Diagonal peaks Diagonal peaks SE with G jk (T) SE with G jk (T) GB+SE with G jj (T) GB+SE with G jj (T) (+) (+) (+) (+) (b) (b) (e) (e) Off-diagonal peaks Off-diagonal peaks GB GB Off-diagonal Off-diagonal peaks peaks (-) (-) EA with EA with (+) (+) G jk (T) G jk (T) (c) (c) (f) (f) Off-diagonal Off-diagonal peaks peaks Total spectrum Total spectrum (-) (-) EA with EA with at T=1000 fs at T=1000 fs G jj (T) G jj (T)   (cm -1 )   (cm -1 )   (cm -1 )   (cm -1 )

Time Two-dimensional spectroscopy 100 fs of electronic couplings in photosynthesis Numerically simulated 2D spectra 200 fs 300 fs  t 600 fs   1000 fs 100 fs < Waiting Time ( T ) < 2000 fs COUPLINGS  Ex. TRANSFER Nature 434, 625 (2005)   (cm -1 )   (cm -1 )