LABORATORY OF MOLECULAR PHOTOCHEMISTRY
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 Head of the department:
Salikhov Kev Minullinovich,
Professor, Dr. Sc., Corresponding member of RAS.
tel.: (843) 272 50 44, 272 05 03
e-mail: salikhov@kfti.knc.ru
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Deputy head of the laboratory:
Lobkov Vladimir Sergeevich,
Senior researcher, Ph.D.
tel.: +7 (843) 231 91 20
e-mail: lobkov@kfti.knc.ru
Main fields of research:
Radiospectroscopy. Chemical reactions and quantum coherence: femtochemistry, spin chemistry. Atomic molecular processes on the solid-state surface, atomic force microscopy.
Staff and postgraduate students:
Moiseev C.A. (Dr.Sc.), Osokin D.Ya. (Dr.Sc.), Shtyrkov E.I. (Dr.Sc.), Matukhin V.L. (Dr.Sc.), Voronkova V.K. (Ph.D.), Galyautdinov M.F. (Ph.D.), Kandrashkin Yu.E. (Ph.D.), Galeev R.T., Vasina O.A., Gnesdilov O.I., Ilmatova D.V., Korobchenko L.V., Kurbatova N.V., Matukhina L.E., Tseitlin M.P., Andreeva A.I., Abdrakhmanova S.A., Khusnutdinov R.R., Chernyaev S.V., Mursalimov L.P., Lapaev, Tseitlin O.A. D.V.
Main fields of research:
Spin and molecular dynamics of elementary photochemical processes, including development of radiospectroscopy and laser optical spectroscopy techniques as means of this investigation.
Directions and results of research
Spin dynamics and time-resolved EPR spectra of separated charges in the reaction center of bacterial and plant photosynthesis. The following effects have been theoretically predicted: quantum beats of the intensity of the EPR spectral lines, an anomalous phase in the signal of the primary spin echo, a "pseudo-echo" signal generated by a single microwave pulse, a phase shift in quantum beats of the intensity of the EPR lines in a sequence of electron-hole pairs in the reaction center of the photosynthesis. A new conceptual approach to investigating spin dynamics of short-lived electron-hole pairs in the photosynthetic reaction center is being developed: it is proposed to introduce additional spins-observers into the reaction center. Thus, one could obtain information about the charges formed at the initial stage of the photosynthesis just by measuring the state of the spins-observers.
Theoretical foundations of quantum interference of photons in macroscopic coherent media have been worked out. On the basis of this theory experiments for the observation of novel manifestations of the non-classical nature of photons, realized at their interaction with the medium, have been proposed.
Theoretical and experimental foundations of muon spin echo have been developed.
Chemically induced nuclear (CINP) and electron (CIEP) polarization. Stimulated nuclear polarization (SNP). A program of theoretical and experimental investigations of nuclear polarization effects in photochemical reactions of organophosphorous compounds is implemented. An experimental unit for carrying out these investigations has been created and the computer software for calculating the CINP and SNP effects has been developed. A series of new substances promising for spin chemistry have been synthesized.
An experimental unit designed for experiments on optical detection of EPR spectra of spin-correlated radical pairs has been created. Narrow holes in EPR spectra of radical pairs, detected through recombination luminescence or on the basis of stimulated nuclear spin polarization, have been theoretically predicted.
EPR and EPR imaging. An algorithm of the EPR imaging of conductive bodies was developed for the systems inhomogeneous in one dimension.
EPR is used to investigate spin-spin interactions in cluster and low-dimensional systems with rare-earth ions involved. An anomalous shift of the EPR line has been theoretically predicted and experimentally found for paramagnetic centers having relatively slow relaxation time and coupled through exchange interaction with their fast-relaxing partners.
Spectroscopy of ultrafast processes. Femtochemistry. Femtosecond laser spectroscopy is used to investigate kinetic peculiarities and ensuing coherent phenomena in various organic compounds. The femtosecond coherent anti-Stokes scattering was employed to investigate vibrational dynamics of nitrobenzene molecules. Two stages in the damping of molecular oscillations have been discovered: the rapid stage (1.25 ns) and the slow one (10 ns). Besides, a strong effect of the polarization of the probe field on the decay kinetics of the signal has been established. Kinetic features of free charge carriers in silicon at femtosecond laser excitation have been studied and the coefficient of the ambipolar diffusion has been obtained.
NQR -based investigations of the local charge distribution in molecular and ionic crystals; development of new techniques and applications of multipulse NQR spectroscopy. The laboratory was the first to observe the echo effect in an effective field of multipulse sequences. A new NQR imaging method in the toggling reference frame has been proposed. The NQR data provided information about the oxygen and magnetic ordering in lanthanum high-temperature superconductor ceramics.
Development of the experimental hardware.
The work aimed at creating a time-resolved EPR spectrometer on the basis of a Bruker ER 200-E-SPC spectrometer has been completed. An EPR spectrometer designed to carry out time-resolved experiments on the EPR of spin-correlated pairs has been upgraded. The possibility to use an NQR spectrometer as an experimental unit for dealing with quantum computer problems is being studied. To this end this NQR spectrometer is being modernized - an additional transmitter is being introduced to enable simultaneous irradiation of the spin system on two transitions. The work on modernization of the femtosecond laser spectrometer has been completed. With respect to its dynamical characteristics, it is in no way inferior to the best foreign models.
Contacts with the other institutions, international co-operation
- A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan
- Institute of Chemical Physics of RAS, Moscow
- Institute of Chemical Kinetics and Combustion of the Siberian Branch of RAS, Novosibirsk
- Institute of Physics, Berlin Free University, Berlin, Germany
- Lund University, Lund, Sweden
Basic publications
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Salikhov K.M., van der Est A., Stehlik D.: The Transient EPR Spectra and Spin Dynamics of Coupled Three-Spin Systems in Photosynthetic Reaction Centers. Appl. Magn. Reson. 16, 101-134 (1999).
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Salikhov K.M., Galeev R.T.: Composite Structure of the Stimulated Nuclear Spin Polarization Detected EPR Spectra of the Spin-Correlated Radical Pairs in High Magnetic Fields. Mol. Phys. 95, 1005-1012 (1998).
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Tseitlin M.P., Aminov K.L., Salikhov K.M.: Magnetic Resonance Spectrum of Localized Spins in Conductive Materials in a Linear Field Gradient Appl. Magn. Reson. 16, 325-340 (1999).
- Moiseev S.A.: Photon Interferrention Delayed in Time and Spin Echo in Media with Phase Memory. Opt. Spectrosk. 83, 280-294 (1997)
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Moiseev S.A., Mustafin R.G., Nikiforov V.G., and Suleimanov N.M.: Muon Spin Echo in Zero External Magnetic Field. Phys.Rev. B61,5891- 5994 (2000).
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Lobkov V.S., Moiseev S.A., Negrashov I.V., Salikhov K.M.: Observation of Molecular Vibrations in Nitrobenzene by the Femtosecond Time-Resolved Impulsive Stimulated Raman Scattering. SPIE, vol. 3239, 347 - 351 (1997).
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Kandrashkin Yu.E., Salikhov K.M.: Effect of Spin Coherence in EPR Spectroscopy of Separated Charges in Photosynthetic Reaction Center. Usp. Fiz. Nauk, 166, 207 - 210, 1996 .
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Salikhov K.M., Galeev R.T., Voronkova V.K., Yablokov Yu.V., Legendziewicz J.: The Reverse Shift of the EPR Line of Paramagnetic Centers Coupled to Species with a Fast Paramagnetic Relaxation. Appl. Magn. Reson. 14, 457 - 472 (1998).
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Osokin D.Ya., Shagalov V.A.: QR transient nutation and rotary echoes in the effective field of multiple-pulse sequences. Solid State Nuclear Magn. Reson. 10 , 63-72 (1997).
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