Direct observation of the (forbidden) S-1 state in carotenoids

• Carotenoids are involved in a variety of biological functions, yet the underlying mechanisms are poorly understood, in part because of the long-standing difficulty in assigning the location of the first excited (S-1) state. Here, we present a method for determining the energy of the forbidden S-1 state, on the basis of ultrafast spectroscopy of the short lived level. Femtosecond transient absorption spectra and kinetics of the S-1 --> S-2 transition revealed the location of the intermediate level in two carotenoid species involved in the xanthophyll cycle, zeaxanthin and violaxanthin, and yielded surprising implications regarding the mechanism of photoregulation in photosynthesis.

Subject headings

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Keyword

dependence

photophysics

fluorescence

spectroscopy

energy

photosynthesis

spheroidene

dissipation

xanthophyll cycle

internal-conversion rate

Publication and Content Type

art (subject category)

ref (subject category)