Ultrafast excitation energy transfer and exciton-exciton annihilation processes in isolated light harvesting complexes of photosystem II (LHC II) from spinach

Journal Article · Thu Nov 17 00:00:00 EST 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100097a004· OSTI ID:6604528

Bittner, T; Wasielewski, M R ^[1]; Irrgang, K D; Renger, G ^[2]

---

1. Argonne National Lab., IL (United States)
2. Max-Volmer-Institut, Berlin (Germany)

Excitation energy transfer and exciton-exciton annihilation in the isolated light-harvesting chlorophyll a/b protein complex of spinach photosystem II (LHC II) has been studied by two-color absorption difference spectroscopy with femtosecond time resolution. After selectively exciting Chl b at 645 nm, the transient absorption changes were monitored at wavelengths where either Chl b (655 nm) or Chl a (680 nm) dominates the absorption of LHC II. From the good correspondence of the lifetimes obtained from a numerical analysis of the very fast relaxation in the Chl b absorption band (160 [+-] 20 fs) and the rise kinetics in the Chl a absorption band (145 [+-] 20 fs), it is suggested that the Chl b [yields] Chl a excitation energy transfer occurs on a time scale of about 150 fs. In addition, at both probe wavelengths (655 and 680 nm) lifetimes of 3-7 ps were observed which likely arise from excitation energy transfer processes connected with spectral shifting. The kinetic curves of the transient absorption changes at 680 nm show a remarkable intensity dependence which is ascribed to exciton-exciton annihilation. Since at a probe wavelength of 655 nm no intensity effect on the kinetics was observed, it is concluded that annihilation processes preferably occur among excited singlet states of Chl a molecules. 28 refs., 6 figs.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6604528
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 98:46; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
CHLOROPHYLL
PHOTOSYNTHESIS
ABSORPTION SPECTROSCOPY
EXCITONS
FLUORESCENCE
LASERS
SPINACH
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
FOOD
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
LUMINESCENCE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYTOCHROMES
PIGMENTS
PLANTS
PORPHYRINS
PROTEINS
QUASI PARTICLES
SPECTROSCOPY
SYNTHESIS
VEGETABLES
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
400102 - Chemical & Spectral Procedures
400500 - Photochemistry
550200 - Biochemistry