Directed energy transfer due to orientational broadenning of energy levels in photosynthetic pigment solutions
Directed energy transfer due to orientational broadenning of energy levels in photosynthetic pigment solutions / A.N. Rubinov, E.I. Zenkevich, N.A. Nemkovich, V.I. Tomin // Journal of Luminescence. – 1982. – Vol. 26, No 4. – P. 367-376.
The directed non-radiative energy transfer through monomeric molecules of chlorophyll “a” and pheophytin “a” at high concentrations (c ~ 10⁻²) in a rigid matrix of polyvinylbutyral has been found by using the nanosecond laser spectrofluorimeter. The phenomenon is caused by orientational broadening of pigment molecular spectra owing to its interaction with a solvent. The observed temporal shift of the luminescence spectrum to the red region in a nanosecond time scale as well as the red shift of the time integrated spectrum at a high concentration of pigment molecules and the monotonic growth of the luminescence lifetime with a shift to the red region of the spectrum served as indications of the directed energy transfer in the sample. The non-radiative energy transfer from monomeric molecules towards aggregates is also directly demonstrated by the deformation of instantaneous luminescence spectra in the long-wavelength range (λ > 700 nm). The role and the possibility of the directed energy transfer between molecules with orientationally broadened spectra in the biological systems are discussed.