Title page ChemPhysChem 5/2007: Relaxation of excited states in protonated adenine

The time-resolved study of isolated chromophores has a long tradition at MBI. Dirk Nolting and co-workers have now extended this method to protonated biomolecules. For the DNA base adenine, an accelerated transformation from electronic to nuclear motion was observed, a property that counteracts destructive photochemical processes.
The title page shows a potential energy surface for the protonated adenine. In the foreground is the structure of the cold ground state before photoexcitation. In the background, the structure is deformed to non-planar geometry after UV photoexcitation. The structural change leads to faster internal conversion and was investigated by transient mass spectroscopy with femtosecond pump-probe pulses.
More information: ChemPhysChem (April 2, 2007)