Femtosecond dynamics Femtosecond dynamics and near-field microscopy and near-field microscopy

of chemical and biological objectsof chemical and biological objects

A.N. Petrukhin, O.M. Sarkisov

Institute of Chemical Physics

Moscow, Russia

1. Femtosecond dynamics of bifunctional molecules.

2. Near-field microscopy of lipofuscin granules from human eyes.

Photochromic reaction ESIPT reaction

OHN

CH

h

= 900

O

CH

N+HN

O

C H3C H3

C H3

N

УФ C H3C H3

C H3

N

N

O

C-O bond cleavage: 250 - 400 fs

Formation of intermediate X: 300-450 fs

Formation of colored photoproduct (550-600 nm):

1 - 3 ps

Excited state intramolecular proton transfer (ESIPT): < 80 fs

Formation of twisted structure: 0.3 – 4.4 ps

Formation of colored photoproduct (480-500 nm): 3.8 – 14 ps

S.A. Antipin, A.N. Petrukhin, F.E. Gostev, V.S. Marevtsev,A.A. Titov, V.A. Barachevsky, Yu.P. Strokach, O.M. Sarkisov, Chem. Phys. Lett. 331 (2000) 378.

F.E. Gostev, A.N. Petrukhin, A.A. Titov, V.A. Nadtochenko, A.V. Metelitsa, V.I. Minkin, O.M. Sarkisov, Rus. Chem. Bul. 2004. 23 , 11 3-14.

h

N O

NN

C

OHCH3 CH3

CH3 H

NO

NN

C

OHCH3 CH3

CH3NO2

H

NO

NN

C

OHCH3 CH3

CH3

BrH

Bifunctional molecules: compounds 1-3

1:

2:

3:

Does proton transfer take place?

Pump: 405 nm, 40 fs

Probe: Supercontinuum,

410-800 nm

Experimental setup

Photoinduced absorption dynamics

Photoinduced absorption dynamics

Product yield ratio dependence on pump energy

Compounds 1,2

S0

S1**

S1K* S1

K S0K

S1* X B

BS0K

S0K

B

120 fs

800 fs

20 ps400 fs

3 ps

B – photochromic product

S0K – ESIPT product

ESIPT

C-Ocleavage

Product yield ratio dependence on pump energy

Compound 3

S0

S1** S1

K* S1K S0

K

S2* X B

850 fs 3 ps

450 fs 21 ps

B

S0K

S0K

B

120 fs

B – photochromic product

S0K– ESIPT product

C-Ocleavage

ESIPT

Compound 1. Kinetic curve at 510 nm

Pump pulse chirp influence on wave packet motion

Pump pulse chirp influence on product yield ratio

Time delay = 200 ps

2. Near-field microscopy of lipofuscin granules from human eyes.

Near-field microscopy. Experimental Setup.

200 nm

Single LF granule. Atomic-force microscopy.

Topography

Phase contrast

Single LF granule. Near-filed microscopy.

Topography

Transmission at 410 nm

Single LF granule. Near-filed microscopy.

Topography

Fluorescence spectra

Two photon microscopy of LP granules

Fluorescence decay of LH granules under 400 nm fs irradiation

Fluorescence decay – epoxide formation?

Prof. Oleg Sarkisov

Prof. Victor Nadtochenko

Andrey Titov

Fyodor Gostev

Andrey Petrukhin

Andrey Frolov

Alexander Sobennikov

Arseniy Aybushev

Artem Astafyev

Ivan Shelaev

Pavel Zolotavin

Institute of Chemical Physics

Moscow, Russia

Thank you very much!

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