Two-Dimensional Spectroscopy of Chlorophyll a Excited-State Equilibration in Light-Harvesting Complex II

Parveen Akhtar, Cheng Zhang, Thanh Nhut Do, Gyözö Garab, Petar H. Lambrev, Howe Siang Tan

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Excited-state relaxation dynamics and energy-transfer processes in the chlorophyll a (Chl a) manifold of the light-harvesting complex II (LHCII) were examined at physiological temperature using femtosecond two-dimensional electronic spectroscopy (2DES). The experiments were done under conditions free from singlet-singlet annihilation and anisotropic decay. Energy transfer between the different domains of the Chl a manifold was found to proceed on time scales from hundreds of femtoseconds to five picoseconds, before reaching equilibration. No component slower than 10 ps was observed in the spectral equilibration dynamics. We clearly observe the bidirectional (uphill and downhill) energy transfer of the equilibration process between excited states. This bidirectional energy flow, although implicit in the modeling and simulation of the EET processes, has not been observed in any prior transient absorption studies. Furthermore, we identified the spectral forms associated with the different energy transfer lifetimes in the equilibration process.

Original languageEnglish
Pages (from-to)257-263
Number of pages7
JournalJournal of Physical Chemistry Letters
Volume8
Issue number1
DOIs
Publication statusPublished - Jan 5 2017

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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