Wratchtrup, J. (Stuttgart, Germany): Excitons in pigment - protein complexes
Pigment - protein complexes are use when nature wants to get light (eye, chlorophyll)
Photosynthesis: pigment molecules (antenna complexes) gives energy to reaction centers. Electron-hole pair is generated there. Transport distance 100-300 nm. Efficiency 99%!
Purple bacteria photosynthetic machinery is known at 2A accuracy!
Chlorophylls are arranged in rings
Energy travels from one ring to other
18 clorophyll molecules are in one ring, 10A apart. Their energies make a band
One energy is resonantly selected. Because of disorder one gets a broader energy. Coherently delocalised exciton state. It is a supermolecule