ИСТИНА

The mechanism of coherent modulations [1-3] of the P* state in the transient absorption spectra of the reaction spectra isolated from purple bacteria has been developed. Two water molecules, located between special pair, Ba, Bb chlorophylls and histidine L175 and M202, are supposed to be the ortho-H2O and para-H2O isomers with different magnetic properties. According to our assumption, the interaction of rotational modes of water isomers with the charge transfer states is a reason of coherent modulations of kinetics. The distinctive modulation modes, because of the selection rule [4], were recognized as transition frequencies between rotational resonances of the ortho-H2O monomer. We have modified the system Hamiltonian in order to take into account the rotational modes of ortho-H2O [4]. Evolution of the density matrix was calculated in the Liouville space. The relaxation Redfield theory of molecular aggregates was used to model kinetics up to 3 ps. The calculated kinetics [4] satisfy the ones measured experimentally [2]. [1] M.H. Vos, J.C. Lambry, S.J. Robles, D.C. Youvan, J. Breton, J.L. Martin (1991), PNAS, 88, 8885. [2] A.G. Yakovlev, A.C. Shkuropatov, V.A. Shuvalov (2000), FEBS Letters, 466, 209. [3] V.I. Novoderezhkin, A.G. Yakovlev, R. van Grondelle, V.A. Shuvalov (2004), Journal of Physical Chemistry B, 108, 7445. [4] R.Y. Pishchalnikov, S.M. Pershin, A.F. Bunkin (2012), Physics of Wave Phenomena, 20(3), 184.