2004/11/17 「光化学の基礎概念と実験技術６」

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析麋郑
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2 C-H (4. ev) 29 nm fs psps nsns Internal conversion Intersystem crossing s s f r f f i isc 4

3 5 Donor Accepter A - D 6

4 Point-dipole μ Mataga-Lippert euation 2 2 e μg S n h( ). a f const 2 a 2 S 2n a - f (Onsager) g e s Stoes-Shift : : : : : n a Bull. Chem. Soc. Jpn., 28, (955), Bull. Chem. Soc. Jpn., 29, (956) α h ( a - f ) / cm ( s -)/(2 s +)-(n 2 -)/(2n 2 +) 7 ( E = h= hc/ h : Planc: J s : c : : m / s : 4nm =.6 J/mol =7.9 cal/mol=.2 ev=25 cm - cal = 4.8 J, ev =.62 x -9 J = 866 cm - 8

5 E = h= hc/ cal = 4.8 J, ev =.62 x -9 J = 866 cm - 6 Energy / (J / mol) Energy / cm Wavelength / nm Wavelength / nm 9 / (cal / mol ) / nm H-H O=O NN C=O Cl-Cl I-I C-H C-C 8 46 C=C CC 2 44 C-Cl 8 55

6 (IVR: intramolecular vibrational Redistribution) fsps psps psps 7.2 t t i i h S t f f f f i i f isc isc f f i S Target Reaction 2

7 7. S h a d isc T A + h A A ( d, ) A A + h (, ) S A A + h (, ) da ( t) d A ( t) dt A ( t) A () exp ( ) t luorescence Intensity d Time / Arbit. unit d I A ( t) I A ( t) A d dt d A I d I 4

8 A + h S isc A A ( d, ) A A + h (, ) S h a d T A A + h (, ) A + Q A or X ( Q : 5 Stern-Volmer Plot da ( t) d Q A ( t) dt A ( t) A () exp ( Q luorescence Intensity d Q Time / Arbit. unit ) t d d d Q d Q Q / M Q 6

9 I d I I Stern-Volmer Plot A ( t) I A ( t) A dt d A d Q I A d A d d I A Q I / I luorescence Intensity Wavelength / nm Q / M 7 Stern-Volmer Plot ( t= t=q luorescence Intensity Q Time / Arbit. unit luorescence Intensity Q Time / Arbit. unit I / I Q / M Q / M 8

10 Stern-Volmer Plot 5 4 Non stationary Quenching A +Q I / I Q / M (AQ) A/(A+AQ) =/(KgQ+) A + Q AQ K g 9 Stern-Volmer Plot A + Q (AQ) I / I Q / M 2

11 / (M s) d =8RTη d =8RTη r A =r B d = r A +r B Birs, J.B. : Photophysics of Aromatic Molecules (97), Wiley- Interscience, London; Berlman, I.B. : Handoboo of luorescence Spectra of Aromatic Molecules (97), Academic Press, NewYor. 22

12 η Kinetics 24

13 ps: τ 25 Transient absorption spectroscopy τ Kinetic transient absorption measurement 26

14 Transient Absorption Spectrum Difference spectrum between the ground-state and the transient state. A=log I(w/o excitation) / I(with excitation) I: monitoring light intensity Transient state passing through the sample Ground-state S n S S Absorbance Ground state (absorption spectrum) Absorbance..5 Absorbance...5. Absorption Bleaching of of the ground transient state species Bleaching of the ground state Absorption of the transient species Transient absorption spectra Wavelength Wavelength Wavelength 27 VDL PM WP ex. SG2 PD2 L WLG S pr. BS ST Pulsed Laser Light Source L SG PD CPU Absorbance (./div.) (a) (b) (c) (d) Wavelength / nm WLG LWPVDL BSSPM SGPDSTCPU h Transient absorption spectra of bianthryl observed at ps following the excitation with a 55 nm laser pulse with 5 ps pulse width. (a) in n-hexane, (b) in ethyl acetate, (c) in acetonitrile, and (d) adsorbed on the porous glass. J. Phys. Chem.,. A 6 (22)

Kinetic transient absorption measurement Absorbance..2.. - 2 4 5 Time / ps Schematic diagram of dual OPA femtosecond laser system.

15 Kinetic transient absorption measurement Absorbance Time / ps Schematic diagram of dual OPA femtosecond laser system. BS (beam sampler), AP (aperture), L (ND filter), WP (polarization wave plate), VND (variable ND filter), DL (optical variable delay line with retroreflector.), DM (photodetector for the monitoring beam), DR (photodetector for the reference beam), and DE (photodetector beam for the probe beam intensity). Chem. Phys. Lett., 7,2 (2) 4 Time profile of the transient absorbance of bianthryl in acetonitrile, monitored at 68-nm following the excitation with a femtosecond 4 nm laser pulse with 85 fs fwhm. Solid line is the curve calculated on the basis of pulse duration of pump and probe pulses and the time constant of.55 ps. J. Phys. Chem., A 6 (22) (5 fs ). Absorbance Time / fs Oxazine 4 /methanol

2 Absorbance (.5/div.) A-Dhv (A-D) (A - D + ) 4 6 8 Wavelength/nm 6 ps 4 ps ps 2 ps ps ps ps, EADMPP.PRM DMA DMPP/Ethyl Acetate(Exc.

16 2 Absorbance (.5/div.) A-Dhv (A-D) (A - D + ) Wavelength/nm 6 ps 4 ps ps 2 ps ps ps ps, EADMPP.PRM DMA DMPP/Ethyl Acetate(Exc. at 55 nm) ig. E(a) Absorbance.2 t=7 ps. 2 Time / ps DMA DMPP/ethyl acetate (Mon. 545nm, Exc. 55 nm) Donor Chem. Phys. Lett., 7 (999)2- A - D Accepter

17 Chem. Phys. Lett. 78(99) BP + DABCO BP - + DABCO + 4 (p.2) BP BP BH BPK + 2 BOH 5

18 6 BOH BOH + 2 BH BPK BOH BP r d P + Q BP ) ( BH BH BH BH BH Q Q BH BH r T r T r T BOH p d T r T r T BOH r p d r BOH isc f d isc () (2) / BOH / BH / - M / / T r 7 Q ) ( Q BH BH Q BH Q BH BH Q BH BH T r T r T T r T BOH p d T T r T r T BOH r p d r BOH isc f d isc / BOH Q / M Q

19 8 (Stern-Volmer Plot) I / I Q / M ) ( ) ( Q Q Q Q Q Q Q I I I A I I A t A I dt t A d d R d R d d d A d A d A Kinetic Scheme 9 (589nm)

20 Δλ5-nm % ND 4 4

21 P.42 BK7 >4nm >2nm >2nm p.46 4

22 - -2 (S ) (T ) (T ) (S ) diff = /M/s / ( diff O 2 ) = -8 = ns ns - ns 44 (p.44) 45

23 8.5 p

24 (a).5 Absorbance Wavelength / nm h N laser = YAG 55nm (mj/pulse) Hz H + t t dcr I dt l C ln R R l t t ln t ln R I ODα (P)(R) dcr dt t t t R P I l C C R P t l l t ( t) ( t) t t t Saotome et al. Photochem. Photobiol. Sci., 4 (25) (a) Absorbance = 2% 2% 25% ig.(a). (b).25 Absorbance N laser = 25% 2% 2% (b) Absorbance 5 N laser = 7% % N laser Saotome et al. Photochemical & Photobiological Sciences 24, 4, 8 49

25 Summary Kinetics,Mechanism 5 A + Q AQ 5

26 Dynamics (Time-Window 52 PC TCSPC module Laser X-Y stage D PD sample objective counts Time/s time : (D+D2) router D APD EOM BBO Bere 48nm,8MHz pin hole counts Time/ns D : (D+D2) delay APD2 D2 5μm 9ps Events Delay/ns D : D2 5

27 Scan speed. μm/s 5 nm 54

28 Scan speed. μm/s 5 nm 56 defocus Ref. J. Enderlein et al J.Opt.Soc.Am.B,2,2, Polymer,26,47,25-258

29 Defocusing CW (488nm) CCD Cascade 52B 5ms~s frame ~ 295 K PMMA Tg=78K

30 ~ 295 K PMA Tg=282K sec. sec. 6sec. 9sec. PMA =282K) 2sec. 5sec. PMMA=78K)

31 luorescence Imaging with One Nanometer Accuracy (IONA) A. Yildiz, and P. R. Selvin, Acc. Chem. Res. 8, (25). X = /-.9 pixel Y = /-.5 pixel 2.5 nm /pixel 28//8 at 6

32 Single Molecule Tracing (SMT) of a PDI molecule in the unreacted film nm 66 Dt <r 2 > 67

33 Cw 68 25ns Events Events Delay /ns -25 Delay /ns 25

34 A B A B 7 7

09/03/2014 (H. Miyasaka) 2014/09/ C-H (4.3 ev) 290 nm ns 10ns 100fs ps 10

09/03/2014 (H. Miyasaka) 2014/09/ C-H (4.3 ev) 290 nm ns 10ns 100fs ps 10 /9/ http://www.lase.chem.es.osaa-u.ac.jp/ miyasaa@chem.es.osaa-u.ac.jp C-H (. ev) 9 nm nsns s psps s s Intenal convesion Intesystem cossing i isc Dono Accepte A - D 6 (Onsage) Point-dipole μ Mataga-Lippet