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1

Modelling of SubPc Self-Assembly on Ag(111)

100%

Petrauskas V., Tornau E., Lapinskas S.

Acta Physica Polonica A

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2005

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vol. 107

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issue 2

388-391

EN

The ordering of subphthalocyanine molecules into honeycomb and hexagonal close packed patterns on Ag(111) is described using complex Lennard-Jones-type intermolecular potential. We rescale Ag(111) lattice, and take into account an infinite exclusion of first, second, and third neighbours, attraction - of fourth and fifth, and repulsion - of sixth and seventh. The phase diagram is obtained by the lattice gas model using Monte Carlo simulations. Very strong first order phase transitions, causing the two-phase co-existence, are found between disordered and honeycomb as well as between disordered and hexagonal closed packed phases.

2

STM-Induced Luminescence for Alkanethiol Films on Au(111) Surface

100%

Nishitani R., Tateishi Y., Arakawa H., Kasuya A., Sumiyama K.

Acta Physica Polonica A

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2003

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vol. 104

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issue 3-4

269-279

EN

STM-induced luminescence spectra for organic molecule adsorbed Au(111) surfaces were studied, and the influence of STM-tip alloy material on the emission spectra was measured. We observed the STM-tip dependent emission spectra of Au(111). The characteristics of the spectra with Pt-Ir alloy(20%) tip are interpreted in terms of the one-mode type and two-mode type depending on the composition rates. We measured the emission spectra for two different types of molecules, decanethiol and octanedithiol, which have different adsorption structures. The emission spectra for the octanedithiol films were compared with the spectra from clean gold films and the decanethiol films. A spectral change of Au(111) due to adsorption of octanedithiol molecules on Au(111) was observed in the spectral range from 700 through 780 nm while not for the adsorption of decanethiol molecules. The spectral change due to adsorption of octanedithiol molecules is compared with the STS measurements.

3

Simulation of Hydrogen-Induced Reconstruction of Oxygen on Pd(111)

100%

Petrauskas V., Tornau E.

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EN

The oxygen and hydrogen atoms co-adsorption experiment on Pd(111) is modelled using kinetic Monte Carlo method. We consider O-O, H-H, and O-H interactions and several kinetic processes (diffusion, surface and subsurface H-atoms exchange and water-formation reaction) leading to the phase transition (2×2)_O → (√3×√3)_O with increase in H-coverage. We also demonstrate how reverse phase transition (√3×√3)_O → (2×2)_O occurs due to hydrogen dissolution into subsurface in the absence of hydrogen gas. At higher temperature we observe the disappearance of (2×2)_O oxygen islands due to water-formation reaction.

4

Simulation of Reaction-Induced Phase Separation in Surface Alloy

100%

Zvejnieks G., Tornau E.

Acta Physica Polonica A

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2008

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vol. 113

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issue 3

1099-1102

EN

Using kinetic Monte Carlo method we simulate the dynamics of biatomic Au_{0.3}Ni_{0.7} surface alloy separation on Ni(111) due to Ni(CO)_4 out-reaction. The experiment of Vestergaard et al. is modeled by counterbalancing dynamical processes and interactions between reactants. The simulations demonstrate step flow rate increase with CO coverage, c_{CO}, in qualitative agreement with the experiment only for c_{CO} ≲ 0.45 monolayer. Moreover, we demonstrate both CO influence on reaction process and Au domain formation.

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4 Acta Physica Polonica A

2 2008

1 2005

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3 Tornau E.

2 Petrauskas V.

1 Arakawa H.

1 Kasuya A.

1 Lapinskas S.

1 Nishitani R.

1 Sumiyama K.

1 Tateishi Y.

1 Zvejnieks G.

Modelling of SubPc Self-Assembly on Ag(111)

STM-Induced Luminescence for Alkanethiol Films on Au(111) Surface

Simulation of Hydrogen-Induced Reconstruction of Oxygen on Pd(111)

Simulation of Reaction-Induced Phase Separation in Surface Alloy