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Öğe An alternative approach on the calculation of cohesive energy density and isothermal compressibility of alkali metal halides(TAYLOR & FRANCIS LTD, 2017) Kaya, Savas; Kaya, CemalIn the present paper, new and useful theoreticalmethods for the estimation of cohesive energy density (Ced) and isothermal compressibility (k(T)) of alkali metal halides are described. The mentioned theoretical methods include the use of Kaya molecular hardness equation published by us in recent years. Cohesive energy density and isothermal compressibility of alkali metal halides were calculated in the framework of mentioned theoretical methods and the results obtained were compared with both experimental data and the results of previous theoretical methods proposed to calculate the aforementioned quantities, namely cohesive energy density and isothermal compressibility. It is important to note that the results obtained in the study are in good agreement with the available experimental data and with the results of previous theoretical methods. Additionally, we also investigated the correlation with lattice energy of cohesive energy density and isothermal compressibility for alkali halides. [GRAPHICS] .Öğe Anticorrosive Effects of Some Thiophene Derivatives Against the Corrosion of Iron: A Computational Study(FRONTIERS MEDIA SA, 2018) Guo, Lei; Safi, Zaki S.; Kaya, Savas; Shi, Wei; Tuzun, Burak; Altunay, Nail; Kaya, CemalIt is known that iron is one of the most widely used metals in industrial production. In this work, the inhibition performances of three thiophene derivatives on the corrosion of iron were investigated in the light of several theoretical approaches. In the section including DFT calculations, several global reactivity descriptors such as E-HOMO, E-LUMO, ionization energy (I), electron affinity (A), HOMO-LUMO energy gap (Delta E), chemical hardness (eta), softness (sigma), as well as local reactivity descriptors like Fukui indices, local softness, and local electrophilicity were considered and discussed. The adsorption behaviors of considered thiophene derivatives on Fe(110) surface were investigated using molecular dynamics simulation approach. To determine the most active corrosion inhibitor among studied thiophene derivatives, we used the principle component analysis (PCA) and agglomerative hierarchical cluster analysis (AHCA). Accordingly, all data obtained using various theoretical calculation techniques are consistent with experiments.Öğe Bütünleşik jeofizik yöntemlerle Idyma (Muğla) ilk çağ arkeolojik alanının araştırılması(2009) Büyüksaraç, Aydın; İren, Kaan; Kaya, Cemal[Abstract Not Available]Öğe Calculating the CO-factored force constants of tricarbonyl complexes with C-s symmetry(ELSEVIER SCIENCE SA, 2010) Ustun, Elvan; Kaya, CemalThe maximum value of the sum of the interaction constants is used as an additional constraint to solve the CO-factored force fields of tricarbonyl complexes with C-s symmetry. The solution obtained led to the equations by which carbonyl stretching force constants and CO-CO interaction constants can be calculated directly from C-O stretching frequencies of the all-(CO)-C-12-O-16 molecule. The CO-factored force constants and the C-O stretching frequencies of (CO)-C-13-O-16-substituted species were calculated for Fe(CO)(3)(-) and Fe(C4H6)(CO)(3). The results obtained were found to be very close agreement with those obtained from isotopic enrichment studies. (C) 2010 Elsevier B. V. All rights reserved.Öğe A computational study on corrosion inhibition performances of novel quinoline derivatives against the corrosion of iron(ELSEVIER SCIENCE BV, 2017) Erdogan, Saban; Safi, Zaki S.; Kaya, Savas; Isin, Dilara Ozbakir; Guo, Lei; Kaya, CemalIn this computational study, the adsorption and corrosion inhibition properties of some novel quinoline derivatives namely, 2-amino-7-hydroxy-4-phenyl-1,4-dihydroquinoline-3-carbonitrile (Q1), 2-amino-7-hydroxy-4-(p-toly1)-1,4-dihydroquinoline-3-carbonitrile (Q2), 2-amino-7-hydroxy-4-(4-methoxypheny1)-1,4-dihydroquinoline-3-carbonitrile) (Q3) and 2-amino-4-(4-(dimethylamino)pheny1)-7-hydroxy-1,4-dihydroquinoline-3-carbonitrile (Q4) on the corrosion of iron were investigated using quantum chemical and molecular dynamics simulation approaches. Quantum chemical calculations section of the study provides enough calculation and discussion on the relationship between corrosion inhibition and global reactivity descriptors such as E-HOMO, E-LUMO, HOMO-LUMO energy gap (Delta E), chemical hardness (eta), softness (sigma), electronegativity (chi), chemical potential (mu), electrophilicity (omega), nucleophilicity (epsilon), electrons transferred from inhibitors to metal surface (Delta N), initial molecule-metal interaction energy (Delta Psi), total electronic energy (E), the energy change during electronic back-donation process (Delta Eb-d). The adsorption behaviors of studied compounds on Fe (110) surface were investigated with the help of molecular dynamics simulation approach. The binding energies calculated on Fe (110) surface of mentioned quinoline derivatives followed the order: Q4 > Q3 > Q2 > Q1. It should be noted that the results obtained in the study are in good agreement with experimental inhibition efficiency results earlier reported. (C) 2017 Elsevier B.V. All rights reserved.Öğe Copper-Catalysed Allylic Substitution Using 2,8,14,20-Tetrapentylresorcinarenyl-Substituted Imidazolium Salts(WILEY-V C H VERLAG GMBH, 2015) Kaloglu, Murat; Sahin, Neslihan; Semeril, David; Brenner, Eric; Matt, Dominique; Ozdemir, Ismail; Kaya, Cemal; Toupet, LoicUnsymmetrical imidazolium salts, each having one nitrogen atom (N1) substituted by a cavity-shaped TPR group (TPR = 2,8,14,20-tetrapentylresorcinaren-5-yl), were tested in situ as proligands for the copper-catalysed allylic arylation of cinnamyl bromide with arylmagnesium halides. The catalytic systems produced mixtures of linear (l) and branched (b) arylated compounds in variable proportions, with the b/l ratio being the highest (78:22) for the most crowded imidazolium salt used, namely that in which the second nitrogen atom (N2) was substituted by a mesityl group. An N-heterocyclic carbene complex obtained from one of the imidazolium salts was characterised by an X-ray diffraction study.Öğe Deep crustal structure of northwestern part of Turkey(ELSEVIER SCIENCE BV, 2010) Kaya, CemalThe deep crustal structure of the Polatli-Nallihan-Karasu (NW Turkey) area was investigated by Magnetotelluric and Transient Electromagnetic measurements. All measurements were acquired as part of a national project called Crustal Structures of Turkey undertaken by the General Directorate of Mineral Research and Exploration of Turkey (MTA). Magnetotelluric data were collected from 44 stations located along a 250 km northwest to southeast profile crossing in succession the Istanbul Zone, Intra-Pontid Suture, Sakarya Continent, Izmir-Ankara Suture, Tavsanli Zone (the Tauride-Anatolide Belt), Intra-Pontid Suture and Sakarya Continent. After decompositional analysis and strike direction estimation, static shift is corrected by using transient electromagnetic data from MT apparent resistivity data. The processed MT data were inverted to derive a two-dimensional geoelectrical model. The estimated model is interpreted with the help of gravity data observed along the MT lines and using earthquake epicenter which occurred around MT measurement lines. Four layers with distinctive resistivity values dominate the geoelectrical section. The uppermost layer, having resistivity values of 5-35 ohm m can be interpreted as the sedimentary fill. This layer reaches down to about 10 km depth in Haymana Basin. The second layer has resistivity values higher than 110 ohm m and reaches 27 km depth. The first and second layers can be inferred as constituting the upper crust in the general model of the Earth's lithosphere. The third layer underlying the upper crust has resistivity values of 10-30 ohm m corresponding to the lower crust. The fourth layer having high resistivity values (>225 ohm m) can be considered as the upper mantle. The depth of the boundary separating the crust from the upper mantle (Moho) varies between 20 and 40 km. High conductive zones between the Istanbul Zone and Sakarya Continent, Sakarya Continent and Tavsanli Zone coincide with high Bouguer gravity anomaly values. It can be inferred from these properties that these zones correspond to the Intra-Pontide Suture and the Izmir-Ankara Suture. Noticeable differences in tectonic characteristics are observed between the southern and northern part of Sakarya Continent in the geoelectrical section. The northern part of the continent is separated by high dip slip faults while the faults in the southern part do not affect the high resistive zone in the deeper part of the section. These faults controlled the development of the Haymana Basin but they do not alter the high resistive zone to form separate blocks. The majority of these faults, which are clearly seen in the geoelectrical section are not evident in the sedimentary fill. These buried faults have not been studied in detail prior to the present study. (C) 2010 Elsevier B.V. All rights reserved.Öğe Density Functional Theory (DFT) modeling and Monte Carlo simulation assessment of inhibition performance of some carbohydrazide Schiff bases for steel corrosion(ELSEVIER SCIENCE BV, 2016) Obot, I. B.; Kaya, Savas; Kaya, Cemal; Tuzun, BurakDFT and Monte Carlo simulation were performed on three Schiff bases namely, 4-(4-bromophenyl)-N'-(4-methoxybenzylidene)thiazole-2-carbohydrazide (BMTC), 4-(4-bromophenyl)-N'-(2,4-dimethoxybenzylidene)thiazole-2-carbohydrazide (BDTC), 4-(4-bromophenyl)-N'-(4-hydroxybenzylidene)thiazole-2-carbohydrazide (BHTC) recently studied as corrosion inhibitor for steel in acid medium. Electronic parameters relevant to their inhibition activity such as E-HOMO, E-LUMO, Energy gap (Delta E), hardness (eta), softness (sigma), the absolute electronegativity (chi), proton affinity (PA) and nucleophilicity (omega) etc., were computed and discussed. Monte Carlo simulations were applied to search for the most stable configuration and adsorption energies for the interaction of the inhibitors with Fe (110) surface. The theoretical data obtained are in most cases in agreement with experimental results. (C) 2016 Elsevier B.V. All rights reserved.Öğe Determination of corrosion inhibition effects of amino acids: Quantum chemical and molecular dynamic simulation study(ELSEVIER SCIENCE BV, 2016) Kaya, Savas; Tuzun, Burak; Kaya, Cemal; Obot, Ime BasseyAmino acids are biologically important organic compounds in the human body which contain two important functional groups namely: -NH2 (amine) and -COOH (carboxylic acid) in their structures. In the present work, corrosion inhibitive performance amino acids such alanine (Ala), methionine (Met), aspartate (Asp), asparagine (Asn), lysine (Lys), arginine (Arg) and histidine (His) were investigated. All quantum chemical calculations related to these amino acids at the B3LYP/6-31G++(d, p) HF/6-31G++(d,p) methods were performed. Corrosion inhibition effects of the subject amino acids were discussed not only in the gas phase but also in the water phase, acetic acid and formic acid. Furthermore, molecular dynamic simulations employing Monte Carlo sampling approach were applied to search for the most stable configuration and adsorption energies for the interaction of the amino acid corrosion inhibitors on Cu (111)/50 H2O interface. A good correlation between theoretical data and experimental data has been obtained. Moreover, arginine that is a basic amino acid the best corrosion inhibitor among amino acids, considered in this study. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.Öğe Force constant calculations for Hg[CO(CO)(4)](2) frorn the CO-factored force field(NATL INST SCIENCE COMMUNICATION, 2007) Kaya, Cemal; Karakas, DuranAn analytical approach to solve the CO-factored force fields of Hg[Co(CO)(4)](2) belonging to D-3d Point group is described here. The approach leads to relationships which allow direct calculation of carbonyl stretching force constants and CO-CO interaction constants from C-O stretching frequencies of an all (CO)-C-12-O-16 molecule. The force constants calculated by these relationships have been found to be in excellent agreement with those obtained from the Cos beta parameter method. In addition, carbonyl stretching frequencies of the mono (CO)-C-13 substituted derivatives of Hg[CO(CO)(4)](2) have been estimated. The results exhibit agreement between calculated and observed frequencies, showing thereby that the analytical approach presented here gives a valid solution to the CO-factored force field of the molecule under study.Öğe Maximum hardness and minimum polarizability principles through lattice energies of ionic compounds(ELSEVIER SCIENCE BV, 2016) Kaya, Savas; Kaya, Cemal; Islam, NazmulThe maximum hardness (MHP) and minimum polarizability (MPP) principles have been analyzed using the relationship among the lattice energies of ionic compounds with their electronegativities, chemical hardnesses and electrophilicities. Lattice energy, electronegativity, chemical hardness and electrophilicity values of ionic compounds considered in the present study have been calculated using new equations derived by some of the authors in recent years. For 4 simple reactions, the changes of the hardness (Delta eta), polarizability (Delta alpha) and electrophilicity index (Delta omega) were calculated. It is shown that the maximum hardness principle is obeyed by all chemical reactions but minimum polarizability principles and minimum electrophilicity principle are not valid for all reactions. We also proposed simple methods to compute the percentage of ionic characters and inter nuclear distances of ionic compounds. Comparative studies with experimental sets of data reveal that the proposed methods of computation of the percentage of ionic characters and inter nuclear distances of ionic compounds are valid. (C) 2016 Elsevier B.V. All rights reserved.Öğe The Nature of the Crustal Structure of the Eastern Anatolian Plateau, Turkey(TAYLOR & FRANCIS LTD, 2010) Yilmaz, Ali; Yilmaz, Huseyin; Kaya, Cemal; Boztug, DurmusThe Eastern Anatolian Plateau (EAP) of Turkey, with an elevation ranging from 1700 to 2000 m, is located between the Eastern Pontide Arc to the north and the Arabian Platform to the south. In this region, pre-Maastrichtian tectonic units representing the crust crop out in only a few localities. As they are covered by Maastrichtian-Quaternary rock units, it is difficult to study the nature and mutual relationships of these pre-Maastrichtian tectonic units. The palaeotectonic units of the EAP comprise two different levels in the present study: (1) The lower level consists of platform-type carbonates and their metamorphic equivalents. These units may represent the Taurus Platform and its metamorphic equivalents. (2) The upper level consists of an ophiolitic-melange prism which is made up mainly of oceanic crust; the prism comprises a complex of ophiolite, ophiolitic melange, and fore-arc deposits. This upper unit represents a subduction-accretion prism and may have originated partly from the North Anatolian Suture to the north, and partly from the South-eastern Anatolian Suture to the south. Continental crustal rocks were thrust over by the ophiolitic melange prism; thus outcrops of them are scarce in the region as they are exposed in tectonic windows through the ophiolitic thrust sheets. The pre-Maastrichtian tectonic units of the EAP are blanketed by Maastrichtian to Quaternary volcanic and sedimentary rock units; these sequences include successive transgressive and regressive intervals and overlie the palaeotectonic units along a pronounced unconformity. Olistostromal units are abundant in the Eocene sedimentary units and were derived from the ophiolites and ophiolitic melange. The Maastrichtian-Quaternary cover is made up of collisional and post-collisional deposits across the whole region. Although the EAP has been experiencing considerable N-S compression, it has not been affected by significant crustal thickening because of the strike-slip tectonic regime that is dominant in the region. (C) 2010 Lavoisier SAS. All rights reservedÖğe A new approach to predicting the carbonyl stretching frequencies of Co-2(CO)(8) with D-3d symmetry(NATL INST SCIENCE COMMUNICATION, 2007) Kaya, Cemal; Karakas, Duran; Uestuen, ElvanThis paper describes a method for determining C-O stretching frequencies of dicobalt octacarbonyl belonging to D-3d point group. The method is based on the variation of fundamental C-O stretching frequencies and C-O stretching force constants of axially substituted X3MCO(CO)(4) (M=Si, Ge, Sn and Ph; X=Cl; Ph and Et) molecules with the dipole moment of X3M-Co(CO)(4) bond. Frequencies of a(lg)((1)) a(2u)((2)) and e(u) modes have been evaluated from the graph of frequency versus dipole moment, and the frequencies of a(lg)((2)) and e(g) modes determined from the equations derived by using the CO-factored force field. The calculated frequencies have been found to be consistent with the experimental values. With the use of the calculated frequencies, the C-O factored force constants of Co-2(CO)(8) with D-3d symmetry have been calculated. In addition. frequencies of mono-(CO)-C-13 substituted species of Co-2(CO)(8) have been estimated and compared with observed frequencies of the species.Öğe A new equation based on ionization energies and electron affinities of atoms for calculating of group electronegativity(ELSEVIER SCIENCE BV, 2015) Kaya, Savas; Kaya, CemalIn particular, in organic chemistry, the electronegativity of functional groups are taken into consideration significantly to predict reaction mechanism and to explain inductive effects of functional groups. In the present study, considering the relationship with charge of the electronic energy for atoms, Sanderson's electronegativity equalization principle and Density Functional Theory (DFT), we have obtained a new equation by which group electronegativity can be calculated from ionization energies (I) and electron affinities (A) of atoms that constitute the group, where the results obtained were compared with equation of Sanderson who proposed that group electronegativity is the geometric mean of atomic electronegativities. For a large number of groups, it was found to be a very close agreement with a standard deviation of 0.12. The advantage of the present equation is that it can be used for ionic groups. In addition, the derived equation can be used to calculate Mulliken and Pauling electronegativities of molecules. (C) 2014 Elsevier B.V. All rights reserved.Öğe A new equation for calculation of chemical hardness of groups and molecules(TAYLOR & FRANCIS LTD, 2015) Kaya, Savas; Kaya, CemalChemical hardness is considered to be a useful theoretical descriptor in many experimental and theoretical studies and this concept has several important applications in chemistry. In this study, an equation for atomic hardness is proposed. Following the equation for atomic hardness which is based on charges, ionisation energies and electron affinities of atoms, a new equation is obtained for the calculation of the chemical hardness of groups and molecules using the atomic hardness equation and the principle of chemical hardness equalisation. Molecular chemical hardness may be calculated using alpha and beta parameters of atoms in a molecule or group through the use of the obtained molecular hardness equation. Furthermore, the advantage of this equation over other equations in the literature is that using this equation the chemical hardness of the charged groups and molecules can also be calculated. Besides, the relationship between molecular hardness and charge of molecule is examined using the results obtained from the new molecular hardness equation, and the partial charges of atoms in molecules are calculated with the help of derived equations.Öğe New insights from the relation between lattice energy and bond stretching force constant in simple ionic compounds(PERGAMON-ELSEVIER SCIENCE LTD, 2017) Kaya, Savas; Chamorro, Eduardo; Petrov, Dimitar; Kaya, CemalLattice energy and bond stretching force constant are two quantities considered in many fields of chemistry and physics. Both quantities can be used to describe the stability or reactivity of a simple system. In the present study, by inspecting the correlation between lattice energies and bond stretching force constants for some sets of simple ionic molecules having similar bonding type, we present simple and useful equations to estimate the bond stretching force constants of simple ionic compounds. In order to determine lattice energies taken into account in this study, Born-Haber-Fajans (BHF) thermochemical cycle and lattice energy equations proposed by Jenkins and Kaya were used. It is shown that bond force constant of a simple ionic compound can be easily calculated in agreement with its spectroscopic counterpart through its lattice energy value. Percentage deviation values determined considering calculated and observed bond stretching force constants for the tested ionic compounds are pretty small except of some molecules like cesium halides (CsF, CsCl, CsBr). Such small values of percentage deviation probe the reliability and validity of the correlation between lattice energy and bond stretching force constant. (C) 2016 Elsevier Ltd. All rights reserved.Öğe A new method for calculation of molecular hardness: A theoretical study(ELSEVIER SCIENCE BV, 2015) Kaya, Savas; Kaya, CemalThe chemical hardness introduced by Pearson in 1960s is an extremely useful theoretical descriptor. It is apparent that principles such as hard and soft acids and bases (HSAB) and maximum hardness principle (PMH) related with the chemical hardness provide theoretical justifications and explanations for many issues in chemistry. In the present report, a new molecular hardness equation to calculate chemical hardness of functional groups and molecules is derived utilizing the relationship with charge of the electronic energy for atoms, Density Functional Theory, and Datta's global hardness equalization principle. The reliability of the new equation is assessed by comparison with experimental data, the results of Datta's geometric mean equation, and molecular hardness values obtained in the present work. The new equation provides the opportunity to calculate the chemical hardness of molecules from first ionization energies (IE1), first electron affinities (EA(1)) and second ionization energies (IE2) of atoms in the molecules. (C) 2015 Elsevier B.V. All rights reserved.Öğe A novel lattice energy calculation technique for simple inorganic crystals(ELSEVIER SCIENCE BV, 2017) Kaya, Cemal; Kaya, Savas; Banerjee, PriyabrataIn this pure theoretical study, a hitherto unexplored equation based on Shannon radii of the ions forming that crystal and chemical hardness of any crystal to calculate the lattice energies of simple inorganic ionic crystals has been presented. To prove the credibility of this equation, the results of the equation have been compared with experimental outcome obtained from Born-Fajans-Haber- cycle which is fundamentally enthalpy-based thermochemical cycle and prevalent theoretical approaches proposed for the calculation of lattice energies of ionic compounds. The results obtained and the comparisons made have demonstrated that the new equation is more useful compared to other theoretical approaches and allows to exceptionally accurate calculation of lattice energies of inorganic ionic crystals without doing any complex calculations.Öğe A novel method for the calculation of bond stretching force constants of diatomic molecules(PERGAMON-ELSEVIER SCIENCE LTD, 2016) Kaya, Savas; Kaya, Cemal; Obot, I. B.; Islam, NazmulChemical hardness is one of the chemical reactivity descriptors of chemical species and this concept has widely benefited from the development of Density Functional Theory (DFT). In the present report, chemical hardness values for approximately fifty diatomic molecules have been calculated using a new molecular hardness (eta(M)) equation derived by us in recent times. Then, correlation between force constant (k) and chemical hardness for the above mentioned diatomic molecules that situate hydrides, halides, oxides and sulfides among them has been investigated. Consequently, a relation that can be presented by a simple equation between chemical hardness with bond stretching force constants has,been found. (C) 2015 Elsevier B.V. All rights reserved.Öğe The nucleophilicity equalization principle and new algorithms for the evaluation of molecular nucleophilicity(ELSEVIER SCIENCE BV, 2016) Kaya, Savas; Kaya, Cemal; Islam, NazmulIn this work, we have attempted to explore whether the nucleophilicity equalization principle can be conceived analogous to the well-established electronegativity, hardness, and electrophilicity equalization principle. Based on our new definitions of hardness and electronegativity and relying upon the geometric mean principle we proposed a new electronic structure principle, namely the nucleophilicity equalization principle. This approach provides a unified and useful procedure to calculate the nucleophilicity of molecules and groups assuming that nucleophilicity equalization principle is operative and justifiably valid. The results shown here indicate a close resemblance between theory and experiment. (C) 2016 Elsevier B.V. All rights reserved.
