Berlin 2001 – wissenschaftliches Programm

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MO: Molekülphysik

MO 10: Spectroscopy I: Ultra-short Time Spectroscopy

MO 10.9: Vortrag

Donnerstag, 5. April 2001, 17:45–18:00, H1058

Investigation of the cooling dynamics of reversed micelles using picosecond IR pump-probe spectroscopy — •Toralf Patzlaff, Gerhard Seifert, and Heinrich Graener — Fachbereich Physik/ Fachgruppe Optik, Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 8, 06099 Halle/Saale

The cooling dynamics of reversed micelles in n-octane/AOT/water microemulsions was investigated using time-resolved infrared double resonance spectroscopy. In the oil-rich phase of such systems spherical nanoscaled water droplets coated by a monolayer of amphiphile molecules are formed. After excitation of the O-H stretching band of the water molecules followed by ultrafast vibrational relaxation these droplets are brought to a non-equilibrium state characterized by highly increased temperature and pressure. The dynamics of energy flow out of the reversed micelles into the surrounding oil shell was monitored with picosecond time resolution. The thermal relaxation time was determined to be a function of the droplet radii and the initial energy load but does not depend on the droplet concentration i.e. the mean distances between the droplets.