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MO: Molekülphysik
MO 8: Posters Thursday: Dissociation and other Collision Processes
MO 8.16: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT3
The Dissociation and Recombination Dynamics of Iodine Inserted in Microporous Crystalline Porosils of Different Structure — •Günter Flachenecker, Vladimir Ermoshin, Volker Engel, and Arnulf Materny — Institut für Physikalische Chemie, Am Hubland, D-97074 Würzburg, email: amaterny@phys-chemie.uni-wuerzburg.de
The dissociation and recombination dynamics of iodine inside a crystalline matrix was investigated using femtosecond time-resolved pump-probe spectroscopy. Microporous zeolite crystals formed by pure SiO4/2 tetrahedra structures (porosils) served as matrices. A substantial property of the porosils is the charge neutrality of their lattices. This feature makes the porosils a very attractive substance class for the investigation of the influence of the structure of host lattices on the reaction dynamics of their guest molecules, in our case iodine. Inside the DDR porosils the iodine molecules reside isolated from each other in hexagonal cages of a volume of ≈ 350 Å3. Because of the missing iodine-iodine interaction, these cavities are termed “zero-dimensional” structures. In contrast to this, inside TON (silica-ZSM-22) porosils the iodine molecules are embedded in channels having a diameter of ≈ 4 Å. Therefore, they are able to interact with each other along the channel axes (“one-dimensional system”). The microcrystalline structure of FER (silica-Ferrierit) is also determined by channels. Here, the channels cross, which gives rise to a “quasi-two-dimensional” system with respect to the iodine-iodine interactions. In our contribution, we discuss the experimental results reflecting the strong influence of the matrix structure on the caging dynamics.