Dynamics of photoinduced charge transfer and hole transport in synthetic DNA hairpins

The dynamics of photoinduced charge separation and charge recombination pro cesses in synthetic DNA hairpins have been investigated by means of femtose cond transient absorption spectroscopy. The driving force and distance depe ndence of charge transfer processes involving singlet accepters and nucleob ase donors are consistent with a single-step superexchange mechanism in whi ch the electronic coupling between the donor and acceptor is strongly dista nce dependent. The dynamics of reversible hole transport between a primary guanine donor and nearby GG or GGG sequences has also been determined and e stablishes that these sequences are very shallow hole traps.