Femtosecond Dynamics of a Hydrogen-Bonded Model Base Pair in the Condensed Phase: Double Proton Transfer in 7-Azaindole

Femtosecond, real-time dynamics of a hydrogen-bonded model base pair (7-azaindole dimer) in the condensed phase is presented and compared with gas-phase, molecular beam studies. Following the preparation of a wave packet (nonequilibrium state), we resolved the initial decay of the reactive pair and the rise of the tautomer in two solvents. Studies of the isotope effect, solvent viscosity, energy dependence, and polarization anisotropy are consistent with direct and indirect reaction pathways for the double proton transfer on a global potential energy surface.