title: Generation of ultra-short hydrogen atom pulses by bunch-compression photolysis.
abstract: Ultra-short light pulses enable many time-resolved studies in chemistry, especially when used in pump-probe experiments. However, most chemical events are not initiated by light, but rather by collisions. Time-resolved collisional experiments require ultra-short pulses of atoms and molecules--sadly, methods for producing such pulses are so far unknown. Here we introduce bunch-compression photolysis, an approach to forming ultra-short and highly intense pulses of neutral atoms. We demonstrate H-atom pulses of 1.2±0.3 ns duration, far shorter than any previously reported. Owing to its extraordinarily simple physical principles, we can accurately model the method--the model shows H-atom pulses as short as 110-ps are achievable. Importantly, due to the bunch-compression, large (mm(3)) photolysis volumes are possible, a key advantage for pulse intensity. This technique overcomes the most challenging barrier to a new class of experiments on time-resolved collisions involving atoms and molecules.
authors.affiliation: 1] Institute for Physical Chemistry, Georg-August University of Göttingen, Göttingen D-37077, Germany [2] Max Planck Institute for Biophysical Chemistry, Göttingen D-37077, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Kaufmann
authors.affiliation: 1] Institute for Physical Chemistry, Georg-August University of Göttingen, Göttingen D-37077, Germany [2] Max Planck Institute for Biophysical Chemistry, Göttingen D-37077, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Schwarzer
authors.affiliation: Max Planck Institute for Biophysical Chemistry, Göttingen D-37077, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Reichardt
authors.affiliation: 1] Institute for Physical Chemistry, Georg-August University of Göttingen, Göttingen D-37077, Germany [2] Max Planck Institute for Biophysical Chemistry, Göttingen D-37077, Germany.
authors.forename: Alec M
authors.initials: AM
authors.lastname: Wodtke
authors.affiliation: 1] Institute for Physical Chemistry, Georg-August University of Göttingen, Göttingen D-37077, Germany [2] Max Planck Institute for Biophysical Chemistry, Göttingen D-37077, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Bünermann