Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)

O 60.27: Poster

Mittwoch, 16. März 2011, 17:30–21:00, P4

LEED and FTIR spectroscopy studies of CO₂ adsorption at NaF(100) — •Stephan Härtel, Anne Möller, Jochen Vogt, and Helmut Weiss — Chemisches Institut der Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg

In the present work the adsorption system CO₂-NaF(100) was investigated by means of low-energy electron diffraction (LEED) and Fourier transform infrared (FTIR) spectroscopy. According to LEED I(V) analysis the clean NaF(100) surface shows hardly any deviation from the ideal bulk structure but enlarged vibrational amplitudes [1]. Different from other alkali halide cleavage planes such as NaCl(100) or KCl(100) up to now there are few data available dealing with the adsorption behaviour of molecules on this surface. The LEED patterns of CO₂-covered NaF(100) show no evidence for a superstructure but just a decreased intensity of the substrate spots. Apparently the adsorbed molecules do not form a long range order. This result is comparable to that for CO₂ adsorption on LiF(100) and KBr(100). However there are also alkali halide surfaces such as e.g. NaCl [2] where a superstructure could be observed. The adsorption/desorption behaviour was also studied by recording isotherms and isobars by FTIR spectroscopy from which the heat of adsorption was calculated to be 28.6±2.9 kJ/mol which is comparable to the corresponding values in the above mentioned homologous systems.
S. Härtel, J. Vogt, and H. Weiss, Surf. Sci., 604, 1996 - 2001 (2010)
J. Vogt and H. Weiss, J. Chem. Phys., 119, 1105 (2003)