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MO: Molekülphysik

MO 71: Dynamics and Spectroscopy at Interfaces

MO 71.5: Talk

Friday, March 17, 2006, 11:40–11:55, H12

Molecular view of hidden interfaces — •Sylvie Roke — Max-Planck Institute for Metals Research, Heisenbergstr. 3, 70569 Stuttgart

Many important chemical, physical and biological phenomena occur at interfaces of small particles. Most of the tools presently available to study these interfaces use invasive techniques or model systems. Ideally, one would want a non-invasive technique that allows the study of interface structure and dynamics with molecular specificity.

By combining light scattering and femtosecond vibrational sum frequency generation (a technique that has been used to mostly study flat interfaces) we are able to study the interfaces of sub-micron particles in solution on a molecular level. Using a nonlinear Rayleigh Gans Debye model we can extract information about the order and orientation of interface molecules and simultaneously obtain the shape and size of the particles [1]. Two demonstrations of sum frequency scattering will be presented. The first will deal with colloidal dispersions of sterically stabilized silica particles that undergo a gelation transition [2].

Second, we will present valuable insights in the interface properties of lactate particles, which are being used as a new medicine against liver malignancies [3].

[1] S. Roke, et al. Phys. Rev. Lett., 91, 258302 (2003).

[2] S. Roke et al.to be published in J. Phys: Condens Matter., 17, S3467 (2005)

[3] J. F. W. Nijsen et al., Eur. J. Nucl. Med. B, 26, 699 (1999)