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MO: Fachverband Molekülphysik

MO 19: MO Poster 4

MO 19.5: Poster

Donnerstag, 12. März 2020, 17:00–19:00, Empore Lichthof

Far Infrared Spectroscopy of neutral boron clusters using tunable VUV generated by 4-wave mixing — •Sascha Schaller, Alan Günther, Gerard Meijer, and André Fielicke — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany

Previous experiments in combination with calculations [1,2] have shown that Boron cluster are able to form versatile structures like planar, ring-like and cages. To record far-infrared spectra for the neutral clusters, a FIR-VUV two-color ionization scheme can be used [3]. In our first experiments, an F2 excimer laser (157 nm) has been used for the ionization step [4]. As the ionization energy depends on cluster size, there is access to only a limited number of cluster sizes for a given VUV photon energy. To overcome the limitation in photon energy given by the fixed frequency F2 laser (7.9 eV), VUV photons are generated by four-wave mixing in Xenon. In the present configuration, which covers an energy range of 6.5 eV to 8.2 eV, two dye lasers (ω1, ω2) interact in a static gas cell and the resulting (2ω1-ω2) difference frequency is used for ionization. We verified that after creating 7.9 eV photons in this way, the spectra obtained via FIR-VUV ionization reproduce the results obtained via F2 laser ionization.

[1]L. S. Wang, International Reviews in Physical Chemistry 35, 69 (2016). [2]H. J. Zhai et al., Nature Chemistry 6, 727 (2014). [3]M. Putter, G. von Helden, and G. Meijer, Chem Phys Lett 258, 118 (1996). [4]C. Romanescu, D. J. Harding, A. Fielicke, and L. S. Wang, Journal of Chemical Physics 137 (2012).