München 2004 – scientific programme

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MO: Molekülphysik

MO II: HV II

MO II.1: Invited Talk

Tuesday, March 23, 2004, 11:30–12:00, HS 332

Physics and applications of terahertz time-domain spectroscopy on molecular crystals — •Peter Uhd Jepsen, Bernd Fischer, Matthias Hoffmann, and Markus Walther — Department of Molecular and Optical Physics, University of Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg, Germany

Since the late 1980’s terahertz time-domain spectroscopy (THz-TDS) has been developed into a powerful technique for the recording of the dielectric function, represented as the absorption coefficient and index of refraction, in the frequency range 0.1-5 THz. The technique has enabled many important scientific discoveries in the fields of semiconductor physics, atomic physics, chemistry, and biology. In this presentation we will give an overview of the use of THz-TDS in spectroscopy of the lowest vibrational modes of molecular crystals. The technique can be used as a direct and sensitive probe of weak intermolecular interactions, such as van der Waals forces. Furthermore, the technique also allows identification of sealed chemical compounds. Since most illicit materials (such as drugs and explosives) are found in the form of polycrystalline powders, we see interesting applications in the areas of quality control, safety, and security.