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O: Fachverband Oberflächenphysik
O 25: Organic Molecules on Inorganic Substrates III: Adsorption & Growth
O 25.4: Talk
Tuesday, March 19, 2024, 11:15–11:30, MA 043
Vibrational and structural analysis of P2O and P4O monolayers on Ag(111) and Ag(110) — •Ravi Priya, Keda Jin, Weishan Wu, and Peter Jakob — Department of Physics, Philipps-Universität Marburg, Germany
Various phases and associated phase transformations have been studied for 6,13-pentacenequinone (P2O) and 5,7,12,14-pentacenetetrone (P4O) on Ag(111) and Ag(110) using SPA-LEED, FTIRAS & TDS. For P2O, sub-monolayer regime is governed by formation of long rows, aligned along the [110] direction with varying distances between rows. The interaction along the rows is attractive and either weak or slightly repulsive between rows. Close to completion of the monolayer, the streaky LEED patterns turn into sharp, well-defined reflexes. For P4O, attractive intermolecular and molecule-metal interactions lead to ordered and uniform structures for sub-monolayers on both substrates. Lateral ordering is governed by orientation-dependent intermolecular interactions including steric hindrance and hydrogen bonding leading to distinct coverage and temperature-dependent phases on both substrates. IRAS suggests more prominent Interfacial Dynamical Charge Transfer (IDCT) for P4O vs P2O on Ag(111) due to a notably higher DOS of the P4O-LUMO at εF. Molecule-metal interaction is enhanced on Ag(110) vs Ag(111) for both molecules. Intensity, asymmetry, and line shape changes of IDCT-bands reflect the dynamics of vibrational modes and are associated with the DOS of the molecule-LUMO at εF along with the overall strength of respective molecule-metal interaction.
Keywords: Pentacenequinone; Pentacenetetrone; SPA-LEED; FT-IRAS; IDCT