ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 23, Number 5
JKCSEZ 23(5)
October 20, 1979 

The electronic spectrum of marine dinoflagellate antenna pigment, peridinin, has been described in terms of PPP SCF MO CI computations and fluorescence polarization of the peridinin component in photosynthetic pigment complex of Amphidinium carterae. The main absorption band at 470 nm, 1B←A, is polarized nearly along the long molecular axis. There appear to be two π→π* transitions (C and D←A) in the socalled "cis" peak region, and they are polarized roughly parallel to the main B←A absorption. In addition, we have found that the carbonyl group undergoes very 1ittle reorganization of the electronic structure in going from the ground to the 1B excited states of peridinin, while the allenic group shows a strong charge transfer tendency in producing an electron-deficient allente allene group in the excited state.