Theoretical investigaton of AltiNi ternary glusters : density functioanal theory calculations and molecular dynamics simulations

Oymak, Hüseyin
This doctoral study consists of three parts. In the first part, structural and electronic properties of Al_kTi_lNi_m (k+l+m=2,3) microclusters have been investigated by performing density functional theory (DFT) calculations within the B3LYP [which comprises the Becke-88 exchange functional and the correlation functional of Lee, Yang, and Parr] and the effective core potential (ECP) level. Dimers and trimers of the elements aluminum, titanium, and nickel, and their binary and ternary combinations have been studied in their ground states. The optimum geometries, possible dissociation channels, vibrational properties, and electronic structure of the clusters under study have been obtained. In the second part, after an empirical potential energy function (PEF) has been parametrized for the AlTiNi ternary system, stable (minimum-energy) structures of Al_kTi_lNi_m (k+l+m=4) microclusters have been determined by molecular dynamics (MD) simulations. The energetics of the microclusters in 1K and 300 K have been discussed. By performing, again, DFT calculations (within the B3LYP and ECP level), the possible dissociation channels and electronic properties of the obtained clusters have been calculated. In the last part, using the empirical PEF parametrized previously for the AlTiNi ternary system, minimum-energy structures of Al_nTi_nNi_n (n= 1-16) ternary alloy nanoparticles have been determined by performing MD simulations. The structural and energetic features of the obtained nanoparticles have been investigated.


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Yılmaz, Bülent; Yılmaz, Osman; Department of Physics (2007)
This doctoral study consists of two parts. In the first part, the quantum statistical effects on the formation process of the heavy ion fusion reactions have been investigated by using the c-number quantum Langevin equation approach. It has been shown that the quantum effects enhance the over-passing probability at low temperatures. In the second part, we have developed a simulation technique for the quantum noises which can be approximated by two-term exponential colored noise.
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In this thesis study, a new method for finding the optimum geometries of atomic nanoparticles has been developed by modifying the well known diffusion Monte Carlo method which is used for electronic structure calculations of quantum mechanical systems. This method has been applied to homonuclear and heteronuclear atomic clusters with the aim of both testing the method and studying various properties of atomic clusters such as radial distribution of atoms and coordination numbers. Obtained results have been ...
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Aksoy, Ümit; Çelebi, Okay; Department of Mathematics (2006)
This study consists of four chapters. In the first chapter we give some historical background of the problem, basic definitions and properties. Basic integral operators of complex analysis and and Schwarz problem for model equations are presented in Chapter 2. Chapter 3 is devoted to the investigation of the properties of a class of strongly singular integral operators. In the last chapter we consider the Schwarz boundary value problem for the general partial complex differential equations of higher order.
Macroprudential policies, persistence of uncertainty and leverage dynamics a study for real sector in Turkey
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This study consists of three chapters. The first chapter analyses leverage dynamics of Turkish non-financial firms over the last 20 years using a confidential and unique firm-level dataset. Results of panel models reveal that financial development fosters corporate leverage while government indebtedness inhibits it. Both impacts are more pronounced for private firms rather than public firms. Besides, even though improvements in financial development foster long-term debt usage for both SMEs and large firms,...
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The main aim of this study is to discuss the ontology of contemporary construction by considering the recent developments in structures. For this purpose, contemporary transparent surfaces of suspended glass systems are considered. These systems are compared with the framed structures of the modern, and Gothic structures in order to discuss the ontological differences between them. The three systems are compared according to the number of structural systems in the building, the type of structural mat...
Citation Formats
H. Oymak, “Theoretical investigaton of AltiNi ternary glusters : density functioanal theory calculations and molecular dynamics simulations ,” Ph.D. - Doctoral Program, Middle East Technical University, 2004.