Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 12: Morphology Prediction at Interfaces
O 12.9: Talk
Monday, March 7, 2016, 17:00–17:15, S051
Interaction of free-base tetraphenyl porphyrin with MgO(001) surface — •Osman Bariş Malcioğlu1 and Michel Bockstedte1,2 — 1Lehrstuhl f. Theoretische Festkörperphysik, FAU Erlangen-Nürnberg, Erlangen, Germany — 2Chemie und Physik der Materialien, Universität Salzburg, Salzburg, Austria
MgO(001) as a pristine surface is chemically rather inert. Under experimental conditions, step edges, kink-sites and other low coordinated sites are present. Such sites may chemically interact with adsorbates and hence play a role in structure formation. Recently, the metalation of H2TPP with Mg via low coordinated sites on MgO(001) has been demonstrated [1]. The mechanisms underlying this procesess, however, remain unclear. We employ ab-initio molecular dynamics simulations to study how H2TPP may interact with MgO(001) and common low coordinated sites. We find that H2TPP is mobile on the pristine surface since the phenyl rings stericly hinder physisorption at a specific surface site. In the presence of a step or kink site, however, phenyl rings help form a rather stable complex. The molecule aligns at the step or kink such that spontaneous deprotonation of the macrocycle occurs. We present the electronic and structural properties of the adsorbate complex and investigate the photophysical fingerprint of intermediates and the metallized porphyrins using (hybrid) TDDFT, self consistent GW and BSE.
[1] J. Schneider et al., ACS Appl. Mater. Interfaces 7, 22962 (2015).