B850 ring from light-harvesting complex LH2 - Fluctuations in dipole moment orientations of bacteriochlorophyll molecules

Abstract

Interactions with fluctuated environment strongly influence properties of light–harvesting (LH) pigment–protein complexes. Slow fluctuations could be modeled by static disorder. Several types of these fluctuations are connected with changes of ring geometry. Slow fluctuations of bacteriochlorophyll’s dipole moment orientations in B850 ring from LH2 complex of purple bacteria are investigated in present paper. Three modifications of such uncorrelated static disorder type (Gaussian fluctuations of dipole moment orientations in the ring plane, Gaussian fluctuations of dipole moment orientations in a plane which is perpendicular to the ring one and Gaussian fluctuations of dipole moment orientations in arbitrary direction) are taking into account. Distributions of the nearest neighbour transfer integrals are presented and the most important statistical properties are calculated, discussed and compared for different strengths of static disorder.