Alexander Reichmann » People

@mastersthesis{Reichmann2021,

title = {Electronic and Aromatic Structure of Kekulene Studied by Density Functional Theory},

author = {A. Reichmann},

url = {https://homepage.uni-graz.at/en/peter.puschnig/theses/},

year  = {2021},

date = {2021-03-01},

urldate = {2021-03-01},

abstract = {In this work the geometric, aromatic and electronic structure of the polycyclic hydrocarbon kekulene (C48 H24 ) is studied using density functional theory (DFT), the harmonic oscillation model of aromaticity (HOMA), the simple Hückel molecular orbital theory and the probe particle model. 

Experimental results of kekulene adsorbed on the two copper substrates, Cu(111) and Cu(110) are compared to DFT optimized calculations regarding the same metal-organic interfaces as well as theoretical calculations of gas phase kekulene. 

Firstly, the energetically most favorable adsorption position of kekulene on the copper surfaces is obtained. With the optimized configuration the aromatic structure is investigated via the HOMA. In order to further analyze the aromaticity of kekulene, various theoretical models of kekulene are constructed by fixing the geometric structure of kekulene and by fixing electronic structure via the Hückel molecular orbital model. These models, the DFT optimized structures of free kekulene as well as the kekulene/Cu interface are examined in terms of their photoemission intensity, in order to gain insights into their electronic structure. The photoemission momentum maps are compared with photoemission momentum maps gained from angle resolved photoemission spectroscopy measurements. Furthermore, the density of states is investigated for the DFT optimized calculations and the charge density distribution and real space distribution of the frontier orbital nodal structure are investigated of all theoretical configurations. Finally the probe particle model is used in order to simulate non-contact atomic force microscopy and inelastic tunneling spectroscopy measurements. 

From the theoretical, as well as the experimental results, it is concluded that the aromatic Clar’s sextet model is a good predictor of kekulene’s aromatic structure.},

keywords = {},

pubstate = {published},

tppubtype = {mastersthesis}

}