Freitag, 18. November 2016, 15:15 - 16:45 iCal
MATERIALS SCIENCE SEMINAR
"Control and observation of ultrafast dynamics in atoms, molecules and clusters using strong laser fields"
Gastvortrag von Dr. Markus Kitzler (Technische Universität Wien)
Universität Wien, Chemische Institute, Seminarraum 2 (Raum 2124), 1. Stock
Währinger Straße 42, 1090 Wien
Vortrag
The electronic response in nanoscopic objects, such as atoms, molecules and nanostructured surfaces lies in the Petahertz (1 PHz = 103 THz = 1015 Hz) frequency range and supports bandwidths reaching several hundred Terahertz. Such electronic dynamics is best accessed with ultrashort intense laser pulses which provide an extremely high temporal resolution reaching into the attosecond domain and additionally allow for spatial control on the order of interatomic distances on the Ångström scale. Despite the moderate average powers of laser beams, the high peak electric field strength of an ultrashort laser pulse can ionize an atom or break a chemical bond. Thus, the intense few-cycle pulse in a light-matter interaction supplies a driving force as well as a temporal and spatial reference.
In my talk I will review some of our recent research activities on the measurement and control of ultrafast processes in atoms, molecules and small gas clusters with strong laser fields. I will discuss the results of experiments by which we could demonstrate that the outcome of molecular restructuring and fragmentation processes in ionic states of molecules can be pre-determined on sub-femtosecond time-scales. That is, an ultrashort laser pulse can “program” bond breaking and restructuring processes in a photo-dissociating molecule on the time scale of the light oscillation period. During this laser-matter interaction process, electrons can also be trapped in high-lying excited states. It is thought that because of their large spatial extension these states can mediate reactions with neighboring molecules. Such reactions could for example be observed in molecular gas clusters. I will present first experimental results on these trapping processes in argon gas dimers. In these experiments we obtained insight into and control over the trapping process on sub-laser-cycle time-scales.
Veranstalter
Institut für Physikalische Chemie, Universität Wien
Kontakt
Univ.-Prof. Dr. Wolfgang Kautek
Universität Wien
Institut für Physikalische Chemie
0043 664 60277 52470
wolfgang.kautek@univie.ac.at
Erstellt am Mittwoch, 09. November 2016, 00:02
Letzte Änderung am Montag, 14. November 2016, 08:34