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MO: Molekülphysik

MO 25: Poster: Electronic Spectroscopy

MO 25.5: Poster

Tuesday, March 14, 2006, 16:30–18:30, Labsaal

Excitation Spectroscopy of ClF in an Argon Matrix — •Nina Owschimikow, Mizuho Fushitani und Nikolaus Schwentner — Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin

We investigate the B state dynamics of chlorine monofluoride (ClF) molecules embedded in a solid Argon (Ar) matrix at liquid helium temperature for laser excitation wavelengths below and above the gas phase dissociation limit (476 nm). The ClF molecule occupies a single substitutional site in the Ar lattice, and is therefore capable of librational motion [1] and rapid reorientation [2] upon excitation. Frequency resolved excitation spectra of the B state were obtained by monitoring the intensity of the A’ fluorescence. In contrast to results for the non-rotating molecules Cl2 and Br2 the excitation spectra of ClF show no resolved vibrational progression even below the gas dissociation limit. This indicates a large contribution of librational modes to the vibronic transition. Therefore we study the depolarization and thus dynamics of reorientation on ultrafast (ps) and slow (ms) timescales. Additionally, we investigate the bleaching efficiency and its dependence on the excitation wavelength.

[1] T. Kiljunen, M. Bargheer, M. Gühr, N. Schwentner, and B. Schmidt, PCCP 6, 2932 (2004)

[2] M. Bargheer, M. Gühr, and N. Schwentner, J. Chem. Phys. 117, 5 (2002)