Dispersion Corrected DFT Study of Pentacene Thin Films on Flat and Vicinal Au(111) Surfaces

Here we present a density functional theory study of pentacene ultrathin films on flat and vicinal [(455)] Au(111) surfaces. We have performed crystal and electronic structure calculations by using PBE and optB86b-vdW functionals and investigated the effects of long-range van der Waals interactions for different coverages starting from a single isolated molecule up to 4 monolayers of coverage. For an isolated molecule both functionals yield the hollow site as the most stable one with the bridge-60 site being very close in energy in the case of optB86b-vdW. Binding strength of an isolated pentacene on the step edge was found to be much larger than that on the terrace sites. Different experimentally reported monolayer structures were compared and the (6 x 3) unit cell was found to be energetically more stable than the (2 x 2 root 7) and (2 x root 31) ones. For one monolayer films while dispersion corrected calculations favored flat pentacene molecules on terraces, standard (PBE) calculations either found tilted and flat configurations to be energetically similar (on the flat (111) surface) or favored the tilted configuration (on the (455) surface). PDOS calculations performed with the optB86b-vdW functional showed larger dispersion of molecular orbitals over the Au states for the (455) surface when compared with the flat (111) surface, indicating an enhanced charge carrier transport at the pentacenegold interface in favor of the vicinal surface. Starting with the second monolayer, both functionals favored tilted configurations for both surfaces. Our results underline the importance of the dispersion corrections for the loosely bound systems like pentacene on gold and the role played by step edges in determining the multilayer film structure and charge transfer at the organic molecule-metal interface.


Influence of Steps on the Tilting and Adsorption Dynamics of Ordered Pentacene Films on Vicinal Ag(111) Surfaces
METE, ERSEN; Demiroglu, I.; Albayrak, E.; Bracco, G.; Elliatioglu, S.; Danışman, Mehmet Fatih (2012-09-13)
Here we present a structural study of pentacene (Pn) thin films on vicinal Ag(111) surfaces by He atom diffraction measurements and density functional theory (DFT) calculations supplemented with van der Waals (vdW) interactions. Our He atom diffraction results suggest initial adsorption at the step edges evidenced by initial slow specular reflection intensity decay rate as a function of Pn deposition time. In parallel with the experimental findings, our DFT+vdW calculations predict the step edges as the mos...
Pentacene thin films on flat and vicinal Au 111 surfaces
Danışman, Mehmet Fatih; Albayrak, Erol (null; 2015-03-01)
Here we present a structural study of pentacene thin films on flat and vicinal Au(111) surfaces by He atom diffraction measurements and dispersion corrected density functional theory (DFT) calculations. Though experimentally investigated parameter space was limited, no significant difference between the films prepared by different deposition energies was observed. Completion of monolayer coverage was confirmed by simultaneous helium scattering and quartz crystal resonance frequency shift measurements during...
Retraction Free Motion Approach and Its Application in Automated Robotic Edge Finishing and Inspection Processes
Nemer, Mahmoud; Konukseven, Erhan İlhan (null; 2016-12-15)
In this paper, a motion generation algorithm for a six Degrees of Freedom (DoF) robotic hand in a static environment is presented. The purpose of developing this method is to be used in the path generation of the end-effector for edge finishing and inspection processes by utilizing the CAD model of the considered workpiece. Nonetheless, the proposed algorithm may be extended to be applicable for other similar manufacturing processes. A software package programmed in the application programming interface (AP...
Static and free vibration analyses of small - scale functionally graded beams possessing a variable length scale parameter using different beam theories
Aghazadeh, Reza; Dağ, Serkan; Ciğeroğlu, Ender; Department of Mechanical Engineering (2013)
This study presents static and free vibration analyses of functionally graded (FG) micro - beams on the basis of higher order continuum mechanics used in conjunction with classical and higher order shear deformation beam theories. Unlike conventional ones, higher order elastic theories consider the size effect for the beam. Strain gradient theory (SGT) and modified couple stress theory (MCST) are the two common non-classical continuum approaches capable of capturing the size effect. Shear deformation beam t...
Anisotropic elastic and vibrational properties of Ru2B3 and Os2B3: a first-principles investigation
Ozisik, Haci; Deligoz, Engin; Sürücü, Gökhan; Ozisik, Havva Bogaz (2016-07-01)
The structural, mechanical and lattice dynamical properties of Ru2B3 and Os2B3 have been investigated by using a first-principles method based on the density functional theory within the generalized gradient approximation. The single crystal elastic constants are numerically estimated using strain-stress approach. The polycrystalline aggregate elastic parameters are calculated from the single elastic constants via the Voigt-Reuss-Hill approximations. Subsequently, the ductility and brittleness are character...
Citation Formats
E. METE and M. F. Danışman, “Dispersion Corrected DFT Study of Pentacene Thin Films on Flat and Vicinal Au(111) Surfaces,” JOURNAL OF PHYSICAL CHEMISTRY C, pp. 3596–3604, 2015, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35712.