@article{LueftnerMilkoHuppmannetal.2014, author = {L{\"u}ftner, Daniel and Milko, Matus and Huppmann, Sophia and Scholz, Markus and Ngyuen, Nam and Wießner, Michael and Sch{\"o}ll, Achim and Reinert, Friedrich and Puschnig, Peter}, title = {CuPc/Au(1 1 0): Determination of the azimuthal alignment by a combination of angle-resolved photoemission and density functional theory}, series = {Journal of Electron Spectroscopy and Related Phenomena}, volume = {195}, journal = {Journal of Electron Spectroscopy and Related Phenomena}, issn = {0368-2048}, doi = {10.1016/j.elspec.2014.06.002}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120986}, pages = {293-300}, year = {2014}, abstract = {Here we report on a combined experimental and theoretical study on the structural and electronic properties of a monolayer of Copper-Phthalocyanine (CuPc) on the Au(1 1 0) surface. Low-energy electron diffraction reveals a commensurate overlayer unit cell containing one adsorbate species. The azimuthal alignment of the CuPc molecule is revealed by comparing experimental constant binding energy (kxky)-maps using angle-resolved photoelectron spectroscopy with theoretical momentum maps of the free molecule's highest occupied molecular orbital (HOMO). This structural information is confirmed by total energy calculations within the framework of van-der-Waals corrected density functional theory. The electronic structure is further analyzed by computing the molecule-projected density of states, using both a semi-local and a hybrid exchange-correlation functional. In agreement with experiment, the HOMO is located about 1.2 eV below the Fermi-level, while there is no significant charge transfer into the molecule and the CuPc LUMO remains unoccupied on the Au(1 1 0) surface.}, language = {en} } @phdthesis{Scholz2013, author = {Scholz, Markus}, title = {Energy-Dispersive NEXAFS: A Novel Tool for the Investigation of Intermolecular Interaction and Structural Phase Dynamics}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-83839}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2013}, abstract = {In the context of this thesis, the novel method soft X-ray energy-dispersive NEXAFS spectroscopy was explored and utilized to investigate intermolecular coupling and post-growth processes with a temporal resolution of seconds. 1,4,5,8- naphthalene tetracarboxylic acid dianhydride (NTCDA)multilayer films were the chosen model system for these investigations. The core hole-electron correlation in coherently coupled molecules was studied by means of energy-dispersive near-edge X-ray absorption fine-structure spectroscopy. A transient phase was found which exists during the transition between a disordered condensed phase and the bulk structure. This phase is characterized by distinct changes in the spectral line shape and energetic position of the X-ray absorption signal at the C K-edge. The findings were explained with the help of theoretical models based on the coupling of transition dipole moments, which are well established for optically excited systems. In consequence, the experimental results provides evidence for a core hole-electron pair delocalized over several molecules. Furthermore, the structure formation of NTCDA multilayer films on Ag(111) surfaces was investigated. With time-resolved and energy-dispersive NEXAFS experiments the intensity evolution in s- and p-polarization showed a very characteristic behavior. By combining these findings with the results of time-dependent photoemission measurements, several sub-processes were identified in the post- growth behavior. Upon annealing, the amorphous but preferentially flat-lying molecules flip into an upright orientation. After that follows a phase characterized by strong intermolecular coupling. Finally, three-dimensional islands are established. Employing the Kolmogorov-Johnson-Mehl-Avrami model, the activation energies of the sub-processes were determined.}, subject = {Organisches Molek{\"u}l}, language = {en} }