Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 65: Metal substrates: Adsorption of organic / bio molecules VII

O 65.3: Vortrag

Donnerstag, 17. März 2011, 11:45–12:00, PHY C213

Simulation of vibrational spectra of self-assembled monolayers on metal surfaces — •Katrin Tonigold and Axel Groß — Institute for Theoretical Chemistry, Ulm University, D-89069 Ulm, Germany

Vibrational spectroscopy is a common and valuable experimental tool to analyze the chemical composition as well as the orientation of self-assembled monolayers (SAMs) on metal surfaces [1]. The simulation of such vibrational spectra might be helpful for the analysis of experimental spectra and further information might be gained by the theoretical insight in the vibrations occuring at the surface.

In this study vibrational spectra of thiolate-based SAMs on Au(111) have been simulated by means of DFT-GGA-calculations employing two different methods: a harmonic approach using finite differences is compared to an approach using ab initio molecular dynamics simulations showing the influence of temperature and anharmonicity. The impact of different conformers and coverages on vibrational spectra has been considered. Furthermore, the influence of defects such as adatoms or vacancies in the gold surface on the structure of the SAMs and their vibrational spectra is discussed.

[1] Xia Stammer et al., PCCP 12, 6445-6454 (2010).