Photodynamics of doped helium nanodroplets

Datum

23.01.2013

Zeit

16:30 - 18:00

Sprecher

Marcel Mudrich

Zugehörigkeit

Uni Freiburg

Sprache

en

Hauptthema

Physik

Andere Themen

Physik

Host

Quantum Dynamics Seminar

Beschreibung

He nanodroplets are widely used for spectroscopy of embedded atoms, molecules and clusters. Their peculiar properties such as low temperature (0.38K) and superfluidity, their ability to efficiently cool embedded species (‘dopants’), their chemical inertness with respect to dopant-He interaction and to light up to the VUV, make them a nearly ideal spectroscopic matrix. I will present recent experiments that probe the dynamics of doped He nanodroplets induced by laser excitation or ionization of either the dopant or the He droplet. Pico- and femtosecond photoionization spectroscopy of molecules attached to He nanodroplets reveals the dynamics of relaxation of molecules coupled to a superfluid bath. He nanodroplets doped with alkali atoms are a special type of loosely bound system with peculiar photodynamical behaviour. For example, electronically excited Rb atoms tend to dissociate from He droplets as a diatomic molecule, see Fig. 1. When exposed to intense laser fields, dopants can ignite a hot He nanoplasma depending on their position with respect to the droplet surface. Recent synchrotron and FEL studies reveal complex relaxation dynamics such as charge and excitation migration through the droplet and Penning ionization of the dopants.

Letztmalig verändert: 23.01.2013, 08:58:17