title: Ultrafast deactivation processes in aminopyridine clusters: excitation energy dependence and isotope effects.
abstract: Fast excited-state relaxation in H-bonded aminopyridine clusters occurs via hydrogen transfer in the excited state. We used femtosecond pump-probe spectroscopy to characterize the excited-state reaction coordinate. Considerable isotope effects for partially deuterated clusters indicate that H-transfer is the rate-limiting step and validate ab initio calculations in the literature. A nonmonotonous dependence on the excitation energy, however, disagrees with the picture of a simple barrier along the reaction coordinate. An aminopyridine dimer serves as a model for Watson-Crick base pairs, where similar reactions have been predicted by theory.
authors.affiliation: Contribution from the Max Born Institute, Max-Born-Str. 2A, D-12489, Berlin-Adlershof, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Samoylova
authors.forename: V R
authors.initials: VR
authors.lastname: Smith
authors.forename: H-H
authors.initials: HH
authors.lastname: Ritze
authors.forename: W
authors.initials: W
authors.lastname: Radloff
authors.forename: M
authors.initials: M
authors.lastname: Kabelac
authors.forename: T
authors.initials: T
authors.lastname: Schultz
mesh_terms: D000631:Aminopyridines / Q000737:chemistry*; D020029:Base Pairing; D003903:Deuterium / Q000737:chemistry*; D019281:Dimerization; D006859:Hydrogen / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D013053:Spectrophotometry; D013816:Thermodynamics
chemical_list: D000631:Aminopyridines; D006859:Hydrogen; D003903:Deuterium