Functional interpretation of the role of cyclic carotenoids in photosynthetic antennas via quantum chemical calculations

In the paper positions of the energy levels of the first three excited states of cyclic carotenoids are calculated. The pigments studied include the representatives of beta-carotene homologous series containing 5, 7, 9 and 11 conjugated bonds, as well as xanthophylls: zeaxanthin, violaxanthin, lutein, canthaxanthin, astaxanthin and auroxanthin. The results are obtained using quantum chemistry computational methods. The data obtained are discussed in relation to biological functions of carotenoids and their role in the processes related to electronic excitation energy migration involving chlorophyll and oxygen molecules. (C) 2015 Elsevier B.V. All rights reserved.