Broadband 2D Electronic Spectroscopy Reveals a Carotenoid Dark State in Purple Bacteria

摘要

Carotenoids (Cars) play an important role in the photoreactions of photosynthesis (1). Being accessory pigments, they absorb light in the spectral region not accessible to chlorophylls (Chls) and, by subsequent energy transfer to Chls, they increase the spectral cross-section for photosynthetic activity. Moreover, in some organisms, most of the light that drives photosynthesis is absorbed by Cars (2). However, in spite of many years of studies, the exact mechanism of energy transfer from Cars to Chls remains controversial (3, 4), owing to the complex electronic structure of Cars.