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Introduction Computational Details Our Results Summary
Adsorption characteristics of Thiophene on Cu andNi(100): role of van der Waals
Tomas Rojas1
, Jeronimo Matos1
, Abdelkader Kara1
1Physics Department, University of Central Florida
American Physical Society, March Meeting, 2014
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Introduction Computational Details Our Results Summary
1 IntroductionMotivationExperimental Results
2 Computational Details
Calculation DetailsAdsorption Geometries
3 Our ResultsAdsorption EnergiesAdsorption HeightsChanges Electronic StructureCharge Redistribution
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Introduction Computational Details Our Results Summary
Motivation
Thiophene (C4H4S)is a flat 5-membered ring, aromaticmolecule.
Density functional theory (DFT) framework did not includevdWinteraction until very recently.
The main purpose is to evaluate its performancein theadsorption of organic molecules over metallic substrates usingvdW-dF.
Cu(coinage metal) and Ni(reactive magnetic metal).
Experimental Researchon Au(111), Cu[(100), (110)] , Pd[(100), (111)] , Ni(100), Pt [ (111), (100) ].
Computational Researchon Cu(100), Ni(100) and Pd(100).
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Introduction Computational Details Our Results Summary
Experimental Results
1 Imanishi, A., Yagi, S., & Yokoyama, T. (1996). Journal of Electron..., 80, 151154.
I d i C i l D il O R l S
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Introduction Computational Details Our Results Summary
Calculation Details
Vienna Ab-initio Simulation Package (VASP) 1
Five vdW functionals: optB86b, optB88, optPBE, revPBEand rPW86. And their comparision with PBE. 23
Substrates (100): 45 atom, 5 layer slab using periodic
boundary conditions and a minimum of 21 of vacuum.The brillouin zone is sampled using 6x6x1 k-pointmeshes.
Structural optimizationis performed for the molecule andsubstrate separately, followed by a relaxation of the combinedsystem with the last two layers of the substrate fixed.
1G. Kresse and J. Furthmuller, Phys. Rev. B 54,11169 (1996).2J. Klime, D. Bowler, and A. Michaelides, (2011). Phys. Rev. B83(19),
195131.3M. Dion et al. (2004). Phys. Rev. Letters, 92(24),246401.
I t d ti C t ti l D t il O R lt S
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Introduction Computational Details Our Results Summary
Adsorption Geometries
Introduction Computational Details Our Results Summary
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Introduction Computational Details Our Results Summary
Adsorption Energies
Binding Energies
Ead= EMolecule+ ESubstrate
EMolecule/Substrate
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Introduction Computational Details Our Results Summary
Adsorption Heights
Adsorption Heights
Distance between the S atom and the closest metallic atom.
Imanishi, A., Yagi, S., & Yokoyama, T. (1996). Journal ofElectron. . . , 80,151154.
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Introduction Computational Details Our Results Summary
Adsorption Heights
C-S distance
Distance between the S atom and the next C atom.
Imanishi, A., Yagi, S., & Yokoyama, T. (1996). Journal ofElectron. . . , 80,151154.
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Changes Electronic Structure
Partial Density of States dz2 - Cu
The dz2 is the most favorable to couple with the pz orbital of thesulfur atom.
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p y
Changes Electronic Structure
Partial Density of States dz2 - Ni
The dz2 is the most favorable to couple with the pz orbital of thesulfur atom.
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p y
Charge Redistribution
Charge redistribution on Copper
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y
Charge Redistribution
Charge Transfer (Bader Analysis)
Substrate Charge Transfer4 (e)
Cu < 0.14Ni < 0.25
4
Tang, W., Sanville, E., & Henkelman, G. (2009). Condensed Matter : AnInstitute of Physics Journal, 21(8), 084204.
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Charge Redistribution
Ni Bridge 45
5 6
Rupture of the aromatic ring may have influence in the chargetranfer measurements.
5
Orita, H., & Itoh, N. (2004). Surface Science, 550(1-3), 177184.6Mittendorfer, F., & Hafner, J. (2001). Surface Science,492(1-2),2733.
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Summary
Opt-typefunctionals strongly enhance the adsorptionenergies, and reduce the adsorption heightson all surfaces.
Changes in the binding energies on Niare significantly higherthan Cu.
revPBE and rPW86functionals also increase the adsorptionenergies, less strongly than the opt-type functionals, and onlyforcoinage metals. This results from strong repulsive
character at short distances.Charge redistributionis enhanced by opt-type compared torevPBE and rPW86 functionals.
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Poster Session
Session H1: Poster Session II (14:00 - 17:00) 2:00 PM,Tuesday, March 4, 2014 Room: Exhibit Hall F
Abstract: An extensive computational study of theadsorption of thiophene on transition metal surfaces:
role of van der Waals
Authors: Tomas Rojas (Department of Physics, University of
Central Florida), Abdelkader Kara (Department of Physics,University of Central Florida)
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Acknowledgements
This work was made possible by funding from the U.S.Department of Energy Grant No. DE-FG02-11ER16243
The calculations were conducted using computational
resources from NERSCTravel to the APS March Meeting made possible by fundingfrom UCF College of Graduate Studies and UCF StudentGovernment.
Thank you to Dr. Handan Yildirim for helpful discussions andguidance.
Thank you for your attention!
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