Molecular adsorption and multilayer growth of pentacene on Cu(100): Layer structure and energetics
- CNR, Institute of Complex Systems, Sez. Montelibretti, Via Salaria, Km. 29.3, 00016 Monterotondo Scalo (Italy)
We used the partial charge tight binding method to perform a full structure optimization to determine equilibrium adsorption geometries, energetics, and local charge redistribution for molecular adsorption and multilayer growth of pentacene on Cu(100). We found that single molecule adsorption induces only a localized perturbation of the metal lattice which is limited to the topmost layers. At saturation coverage four stable topologies (Brick, Wave, Lines and Zigzag) were identified, all based on pentacene molecules lying flat on the metal surface and with the central phenyl ring adsorbed in top position. Only two (Brick and Wave) out of the four structures are able to sustain multilayer growth. In both cases, assembling beyond the second layer corresponds to a transition from the flat to a tilted geometry, in which the pentacenes adopt a face-plane-face arrangement leading to a herringbone structure. The energetics of the different structure are reported as a function of the molecular number density of the pentacene multilayer by calculating cohesive, stress, and electrostatic energies. The dominant tilted molecular orientation in the pentacene multilayer is in agreement with the average tilt angle of 65 deg. between the molecular plane and the Cu surface derived by near edge x-ray absorption spectroscopy of a four monolayer pentacene film deposited on Cu(100)
- OSTI ID:
- 20957812
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 75, Issue 15; Other Information: DOI: 10.1103/PhysRevB.75.155401; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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