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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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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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