The unique core-mass – radius relation for giants with degenerate helium cores enables us to reconstruct the evolution of three observed double helium white dwarfs with known masses of both components. The last mass transfer phase in their evolution must have been a spiral-in. In the formalism proposed by Webbink (1984), we can constrain the efficiency of the deposition of orbital energy into t...

We develop a quantum scattering model to describe the exciton transport through the FennaMatthews-Olson(FMO) complex. It is found that the exciton transport involved the optimal quantum coherence is more efficient than that involved classical behavior alone. Furthermore, we also find that the quantum resonance condition is easier to be fulfilled in multiple pathways than that in one pathway. We...

We report the transfer of phase structure and, in particular, of orbital angular momentum from near-infrared pump light to blue light generated in a four-wave-mixing process in 85Rb vapor. The intensity and phase profile of the two pump lasers at 780 and 776 nm, shaped by a spatial light modulator, influences the phase and intensity profile of light at 420 nm, which is generated in a subsequent...

The results of ab initio molecular orbital calculations of excited states and electronic couplings (for energy transfer) between the B800 and B850 bacteriochlorophyll a (Bchl) chromophores in the peripheral lightharvesting complex (LH2) of the purple photosynthetic bacterium Rhodopseudomonas acidophila are reported. Electronic couplings are estimated from “supermolecule” calculations of Bchl di...

A D-A (donor-acceptor)-type chromophore may twist or flatten in its excited state to form a TICT (twisted intramolecular charge transfer) state or a PICT (planar intramolecular charge transfer) state, respectively. What is the driving force behind this twisting or planarization? Which geometry will occur for a certain D-A chromophore? To answer these questions, both fragment orbital interaction...