Ronganakis, Rengin Peköz
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Name Variants
R.,Rengin Peköz
R.P.Ronganakis
R., Ronganakis
R.,Rengin Pekoz
R.,Ronganakis
Ronganakis, Rengin Peköz
Ronganakis,R.P.
R., Rengin Pekoz
Rengin Pekoz, Ronganakis
Ronganakis, Rengin Pekoz
Rengin Peköz, Ronganakis
Pekoz, Rengin
Pekoz, R.
R.P.Ronganakis
R., Ronganakis
R.,Rengin Pekoz
R.,Ronganakis
Ronganakis, Rengin Peköz
Ronganakis,R.P.
R., Rengin Pekoz
Rengin Pekoz, Ronganakis
Ronganakis, Rengin Pekoz
Rengin Peköz, Ronganakis
Pekoz, Rengin
Pekoz, R.
Job Title
Doçent Doktor
Email Address
rengin.pekoz@atilim.edu.tr
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Scholarly Output
7
Articles
7
Citation Count
119
Supervised Theses
0
7 results
Scholarly Output Search Results
Now showing 1 - 7 of 7
Article Citation Count: 2Selective adsorption of a supramolecular structure on flat and stepped gold surfaces(Elsevier, 2018) Ronganakis, Rengin Peköz; Donadio, Davide; Department of Electrical & Electronics EngineeringHalogenated aromatic molecules assemble on surfaces forming both hydrogen and halogen bonds. Even though these systems have been intensively studied on flat metal surfaces, high-index vicinal surfaces remain challenging, as they may induce complex adsorbate structures. The adsorption of 2,6-dibromoanthraquinone (2,6-DBAQ) on flat and stepped gold surfaces is studied by means of van der Waals corrected density functional theory. Equilibrium geometries and corresponding adsorption energies are systematically investigated for various different adsorption configurations. It is shown that bridge sites and step edges are the preferred adsorption sites for single molecules on flat and stepped surfaces, respectively. The role of van der Waals interactions, halogen bonds and hydrogen bonds are explored for a monolayer coverage of 2,6-DBAQ molecules, revealing that molecular flexibility and intermolecular interactions stabilize two-dimensional networks on both flat and stepped surfaces. Our results provide a rationale for experimental observation of molecular carpeting on high-index vicinal surfaces of transition metals. (C) 2017 Elsevier B.V. All rights reserved.Article Citation Count: 0A density functional theory study on the structural and electronic properties of PbxSbySez (x plus y plus z=2, 3) clusters(World Scientific Publ Co Pte Ltd, 2018) Ronganakis, Rengin Peköz; Erkoc, Sakir; Department of Electrical & Electronics EngineeringThe structural and electronic properties of neutral ternary PbxSbySez clusters (x y + z = 2, 3) in their ground states have been explored by means of density functional theory calculations. The geometric structures and binding energies are systematically explored and for the most stable configurations of each cluster type vibrational frequencies, charges on atoms, energy difference between highest occupied and lowest unoccupied molecular orbitals, and the possible dissociations channels have been analyzed. Depending on being binary or ternary cluster and composition, the most energetic structures have singlet, doublet or triplet ground states, and trimers prefer to form isosceles, equilateral or scalene triangle structure.Article Citation Count: 23Effect of van der Waals interactions on the chemisorption and physisorption of phenol and phenoxy on metal surfaces(Aip Publishing, 2016) Ronganakis, Rengin Peköz; Donadio, Davide; Department of Electrical & Electronics EngineeringThe adsorption of phenol and phenoxy on the (111) surface of Au and Pt has been investigated by density functional theory calculations with the conventional PBE functional and three different non-local van derWaals (vdW) exchange and correlation functionals. It is found that both phenol and phenoxy on Au(111) are physisorbed. In contrast, phenol on Pt(111) presents an adsorption energy profile with a stable chemisorption state and a weakly metastable physisorbed precursor. While the use of vdW functionals is essential to determine the correct binding energy of both chemisorption and physisorption states, the relative stability and existence of an energy barrier between them depend on the semi-local approximations in the functionals. The first dissociation mechanism of phenol, yielding phenoxy and atomic hydrogen, has been also investigated, and the reaction and activation energies of the resulting phenoxy on the flat surfaces of Au and Pt were discussed. Published by AIP Publishing.Article Citation Count: 50Two-Dimensional Fluorinated Boron Sheets: Mechanical, Electronic, and Thermal Properties(Amer Chemical Soc, 2018) Ronganakis, Rengin Peköz; Konuk, Mine; Kilic, M. Emin; Durgun, Engin; Department of Electrical & Electronics EngineeringThe synthesis of atomically thin boron sheets on a silver substrate opened a new area in the field of two-dimensional systems. Similar to hydrogenated and halogenated graphene, the uniform coating of borophene with fluorine atoms can lead to new derivatives of borophene with novel properties. In this respect, we explore the possible structures of fluorinated borophene for varying levels of coverage (BnF) by using first-principles methods. Following the structural optimizations, phonon spectrum analysis and ab initio molecular dynamics simulations are performed to reveal the stability of the obtained structures. Our results indicate that while fully fluorinated borophene (BF) cannot be obtained, stable configurations with lower coverage levels (B4F and B2F) can be attained. Unveiling the stable structures, we explore the mechanical, electronic, and thermal properties of (BnF). Fluorination significantly alters the mechanical properties of the system, and remarkable results, including direction-dependent variation of Young's modulus and a switch from a negative to positive Poisson's ratio, are obtained. However, the metallic character is preserved for low coverage levels, and metal to semiconductor transition is obtained for B2F. The heat capacity at a low temperature increases with an increasing F atom amount but converges to the same limiting value at high temperatures. The enhanced stability and unique properties of fluorinated borophene make it a promising material for various high-technology applications in reduced dimensions.Article Citation Count: 2Ab initio study of structural and electronic properties of single crystal and core/shell II-VI semiconductor nanowires(Elsevier, 2016) Ronganakis, Rengin Peköz; Department of Electrical & Electronics EngineeringStructural and electronic properties of pristine and H-passivated wurtzite type ZnSe, ZnTe nanowires and ZnX/ZnY (X = Se(Te) and Y = Te(Se)) core/shell nanowires oriented along the [0001] direction have been investigated using first-principles calculations. The changes in the electronic structure of the nanowires due to the quantum confinement and morphology have been searched. Quantum confinement increases the band gap energy as the diameters of ZnSe and ZnTe nanowires decrease. Both homostructured and heterostructured nanowires are found to show a semiconducting character with direct band gaps at Gamma-point. Changing the morphology from homostructured nanowires to heterostructured core/shell nanowires has an important impact on the electronic structure. For instance, the charge separation of electrons and holes along the infinite direction of core/shell nanowires shows a strong preference for electron(hole) states localized inside ZnSe(ZnTe) regions. (C) 2016 Elsevier B.V. All rights reserved.Article Citation Count: 13Dissociative Adsorption of Water at (211) Stepped Metallic Surfaces by First-Principles Simulations(Amer Chemical Soc, 2017) Ronganakis, Rengin Peköz; Donadio, Davide; Department of Electrical & Electronics EngineeringSteps at high-index metallic surfaces display higher chemical reactivity than close-packed surfaces and may give rise to selective adsorption and partial dissociation of water. Inspired by differential desorption experiments, we have studied the adsorption and dissociation of water clusters and one-dimensional wires on Pt(211) by density functional theory and molecular dynamics simulations. These calculations reveal that water at the step edges of Pt(211) adsorbs more weakly than at Pt(221), but partial dissociation of adsorbed water clusters is energetically competitive. We observe that the one-dimensional structure proposed experimentally can be realized only by partially dissociated water wires. In addition, weaker adsorption allows the formation of structures in which a number of water molecules detach from the step and form weak hydrogen bonds with the terrace. This study is further extended to the energetics of small water clusters on (211) surfaces of Ir, Rh, and Pd.Article Citation Count: 29The interaction of halogen atoms and molecules with borophene(Royal Soc Chemistry, 2017) Ronganakis, Rengin Peköz; Pekoz, Rengin; Konuk, Mine; Durgun, Engin; Department of Electrical & Electronics EngineeringThe realization of buckled monolayer sheets of boron (i.e., borophene) and its other polymorphs has attracted significant interest in the field of two-dimensional systems. Motivated by borophene's tendency to donate electrons, we analyzed the interaction of single halogen atoms (F, Cl, Br, I) with borophene. The possible adsorption sites are tested and the top of the boron atom is found as the ground state configuration. The nature of bonding and strong chemical interaction is revealed by using projected density of states and charge difference analysis. The migration of single halogen atoms on the surface of borophene is analyzed and high diffusion barriers that decrease with atomic size are obtained. The metallicity of borophene is preserved upon adsorption but anisotropy in electrical conductivity is altered. The variation of adsorption and formation energy, interatomic distance, charge transfer, diffusion barriers, and bonding character with the type of halogen atom are explored and trends are revealed. Lastly, the adsorption of halogen molecules (F-2, Cl-2, Br-2, I-2), including the possibility of dissociation, is studied. The obtained results are not only substantial for fundamental understanding of halogenated derivatives of borophene, but also are useful for near future technological applications.
