Significance of the excitonic intensity borrowing in the J-/H-aggregates of bacteriochlorophylls/chlorophylls


Gulen D.

PHOTOSYNTHESIS RESEARCH, vol.87, no.2, pp.205-214, 2006 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 87 Issue: 2
  • Publication Date: 2006
  • Doi Number: 10.1007/s11120-005-8408-2
  • Title of Journal : PHOTOSYNTHESIS RESEARCH
  • Page Numbers: pp.205-214
  • Keywords: chlorophylls, chlorosomes, excitonic intensity borrowing, hyperchromism, J-/H-aggregates, optical properties, photosynthesis, porphyrin nanowires, supramolecular antenna complexes, CHLOROFLEXUS-AURANTIACUS, PHOTOSYNTHETIC BACTERIA, GREEN BACTERIA, CHLOROSOMES, DYNAMICS, PIGMENTS, COMPLEX, UNIT

Abstract

A quantitative analysis of the excitonic intensity borrowing for the J-/H-aggregates of the bacteriochlorophylls/chlorophylls (BChls/Chls) in specific, and of porphyrins in general, is presented. The analysis is based on the argument that the mixing between the two energetically well-separated bands, such as the Q and B bands of BChls/Chls, should be considered important if the aggregated system possesses an excitonic superstate. A remarkably simple explanation of the significance of the excitonic intensity borrowing is given: superhyperchromism is manifested by the mediation of interband coupling between the superstates in the two well- separated bands of such aggregates. A comprehensive discussion on the significance of superhyperchromism and on its size-dependence is provided in connection with its effects on the absorption spectra of the BChl/Chl J- and H-aggregates.