Browsing by Author "Böyükata, Mustafa"

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D2 +Nin(T), n=7 and 9, Collision System
(1999) Böyükata, Mustafa; Durmuş, Perihan; Özçelik, Süleyman; Güvenç, Ziya Burhanettin; Jellinek, Julius; 06.01. Bilgisayar Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
In this study the kinetics of reactions of Nin n=7 and 9, clusters with a deuterium D2 molecule are studied via quasiclassical molecular dynamics. Dissociative chemisorption probabilities as functions of impact parameters, collision energies, and a rovibrational state of a molecule are calculated. And the corresponding reactive cross sections are evaluated. Resonance formation in the low collision energy region is discussed.
Effects of molecular rovibrational states and surface topologies for molecule-surface interaction: Chemisorption dynamics of D(2) collision with rigid Ni surfaces
(Springer, 2006) Böyükata, Mustafa; Güvenç, Ziya B.; 120207; 06.01. Bilgisayar Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
A quasiclassical and micro-canonical molecular dynamic simulation techniques have been applied for D(2)(v,j) + Ni-surface collision systems. Dissociative adsorptions of a D(2) molecule on the rigid low index (100), (110) and (111), surfaces of the nickel are investigated to understand the effects of the different surfaces, impact sites and the initial rovibrational states of the molecule on molecule-surface collisions. Interactions between the molecule and the Ni surfaces are mimicked by a LEPS potential. Dissociative chemisorption probabilities of the D(2)(v,j) Molecule ( for the vibrational (v) = 0 and rotational (j) = 0, 1, 3, 10, and for the v = 1,j = 0 states on different impact sites of the surfaces) are presented for the translation energies between 0.001 and 1.0 eV. The probabilities obtained at each collision site have unique behavior for the colliding molecule which is moving along the surface normal direction. It has been observed that at the low collision energies the indirect processes (steering effects) enhance the reactivity on the surfaces. The results are compared to the related studies in the literature.
Estimation of cross sections for molecule-cluster interactions by using artificial neural networks
(Springer, 2006) Böyükata, Mustafa; Koçyiğit, Yücel; Güvenç, Büşra; 120207; 53469; 01. Çankaya Üniversitesi
The cross sections Of D(2) (v,j) + Ni(n) (T), n = 19 and 20, collision systems have been estimated by using Artificial Neural Networks (ANNs). For training, previously determined cross section values via molecular dynamics simulation have been used. The performance of the ANNs for predicting any quantities in molecule-cluster interaction has been investigated. Effects of the temperature of the clusters and the rovibrational states of the molecule are analyzed. The results are in good agreement with previous studies.
Hydrogen hosting of nanoscale boron cluster
(Editura Academiei Romane, 2008) Böyükata, Mustafa; Özdoğan, C.; Güvenç, Ziya B.; 40569; 09.01. Ortak Dersler Bölümü; 06.01. Bilgisayar Mühendisliği; 06. Mühendislik Fakültesi; 09. Rektörlük; 01. Çankaya Üniversitesi
In this paper the Density Functional Results of hydrogen bonded boron micro clusters with B3LYP/6-311++G(d,p) level of computations will be presented. Energetics and structural stability with their possible stable geometries of various selected micro complexes of B(m)H(n) (for m and n <= 11 )boron hydrides have been analysed, and their binding energies with HOMO-LUMO energy gaps have been determined. Mainly, erects of the number of hydrogen atoms on the structures of the boranes are assessed. Moreover, for the cage configurations their distortions have been investigated for the neutral, anionic and cationic cases. It has been observed that there have been two opposing factors for the cage configurations. One of which is the "peeling" of the cage structures by the hydrogen atoms, and the other one is reforming a smaller cage form simultaneously with there remaining boron atoms inside. This is observed mostly for the odd values of m. From our studies it has been also observed that with the bare boronclusters alone, it is difficult to increase the capacity of the hydrogen storage. Therefore, further studies are necessary with the boron complexes
MD study of energetics, melting and isomerization of aluminum microclusters
(Springer, 2006) Böyükata, Mustafa; Güvenç, Ziya B.; 120207; 06.01. Bilgisayar Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Voter and Chen version of an Embedded Atom Model has been applied to study the locally stable structures, energies, melting, isomerization and growth patterns of small aluminum clusters, Al(n), in the size range of n = 2 - 13. Using molecular dynamics and thermal quenching simulations, the global minima and the other locally stable structures have been distinguished from those stationary structures that correspond to saddle points of the potential energy surface. A large number (10000) of independent initial configurations generated at high temperatures has been used to obtain the stable isomers, and the probabilities of sampling different basins of attractions, for each size of the clusters. Their energy spectra have been determined and melting, and isomerization dynamics are investigated.