Femtosecond time-resolved photoelectron spectra of ammonia molecules and clusters
Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie,
Rudower Chaussee 6, D-12489 Berlin, Germany
2 CNRS, Laboratoire de Photophysique Moleculaire, Université de Paris-Sud, F-91405 Orsay, France
Accepted: 9 October 1997
The first femtosecond pump-probe photoelectron spectroscopy experiment for neutral clusters is reported. The state of ammonia molecules and clusters is excited with 120 fs pulses at 200 nm and probed by ionisation at 267 or 400 nm. Ions and electrons are detected in coincidence. The high repetition rate of the fs laser allows one to reduce the coincidence rate per laser pulse to less than 0.05 per pulse so that photoelectrons and photoions can be correlated unambiguously. The energy flow in the excited neutral cluster states is followed in real time, and the energy content in the ionic clusters can be related to the fragmentation patterns.
PACS: 36.40.-c – Atomic and molecular clusters / 34.30.+h – Intramolecular energy transfer; intramolecular dynamics; dynamics of van der Waals molecules / 33.60.Cv – Ultraviolet and vacuum ultraviolet photoelectron spectra
© EDP Sciences, 1997