6 results
Search Results
Now showing 1 - 6 of 6
Article Citation - WoS: 10Citation - Scopus: 9A Computational Study on 4,7-Di(furan Monomer and Its Oligomers(Springer, 2014) Kayi, Hakan; Kayı, Hakan; Kayı, Hakan; Chemical Engineering; Chemical EngineeringThe energy gap, Eg, between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels that determines the electronic and optical properties of 4,7-di(furan-2yl)benzo[c][1,2,5]thiadiazole (FSF) polymer is calculated by performing quantum chemical calculations. First, we theoretically investigated the most stable conformers of FSF monomer and its corresponding oligomers at the B3LYP/6-31G(d) and B3LYP/LANL2DZ levels of theory. We reveal the theoretical molecular structure of this very recently synthesized novel monomer and its oligomers for the first time in the literature. Our results from the B3LYP/6-31G(d) calculations indicated that FSF polymer has a low HOMO-LUMO gap of 1.55 eV to be in good agreement with the experiments. Experimental design and synthesis of novel conjugated polymers require time-consuming and expensive procedures. The findings from this study are promising for the use of computational methods in the design of the novel conjugated polymers, and help to narrow the materials to be used in design and synthesis of conjugated polymers with desired properties.Article Citation - WoS: 9Citation - Scopus: 10A Theoretical Investigation of 4,7-Di(furan Donor-Acceptor Type Conjugated Polymer(Elsevier, 2015) Kayi, Hakan; Elkamel, AliQuantum chemical calculations are performed using density functional theory (DFT) to investigate the HOMO-LUMO energy gap of the 4,7-di(furan-2-yl)benzo[c][1,2,5]selenadiazole-based (FSeF) donor-acceptor type conjugated polymer which ascertains the optoelectronic properties and plays a crucial role, especially in polymeric solar cell applications. In this paper, the most stable conformers of the FSeF monomer and its corresponding oligomers are investigated at the B3LYP/Def2TZV and B3LYP/LANL2DZ levels of theory, and their molecular structures are revealed. The band gap of the polymer is determined by linear-fitting and extrapolation of the DFT data. This gap is found to be 1.44 eV and 1.45 eV by the B3LYP/Def2TZV, and B3LYP/LANL2DZ with PCM calculations, respectively. Our theoretical findings related to the band gap of the FSeF polymer (PFSeF) are in good agreement with other experimental studies in the literature and, hence, the theoretical methods used in this study are promising for the design of similar donor-acceptor type novel conjugated polymers. (C) 2014 Elsevier B.V. All rights reserved.Article Citation - WoS: 2Citation - Scopus: 3Experimental and Theoretical Investigation of the Reaction Between Co2 and Carbon Dioxide Binding Organic Liquids(Tubitak Scientific & Technological Research Council Turkey, 2016) Tankal, Hilal; Yuksel Orhan, Ozge; Alper, Erdogan; Ozdogan, Telhat; Kayi, HakanThe reaction kinetics of CO2 absorption into new carbon dioxide binding organic liquids (CO(2)BOLs) was comprehensively studied to evaluate their potential for CO2 removal. A stopped-flow apparatus with conductivity detection was used to determine the CO2 absorption kinetics of novel CO(2)BOLs composed of DBN (1,5-diazabicyclo[4.3.0]non-5-ene)/1-propanol and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene)/1-butanol. A modified termolecular reaction mechanism for the reaction of CO2 with CO(2)BOLs was used to calculate the observed pseudo-first order rate constant k(0) (s(-1)) and second-order reaction rate constant k(2) (m(3)/kmol.s). Experiments were performed by varying organic base (DBN or TBD) weight percentage in alcohol medium for a temperature range of 288-308 K. It was found that k(0) increased with increasing amine concentration and temperature. By comparing using two different CO2BOL systems, it was observed that the TBD/1-butanol system has faster reaction kinetics than the DBN/1-propanol system. Finally, experimental and theoretical activation energies of these CO2BOL systems were obtained and compared. Quantum chemical calculations using spin restricted B3LYP and MP2 methods were utilized to reveal the structural and energetic details of the single-step termolecular reaction mechanism.Article Citation - WoS: 5Citation - Scopus: 4Computational Analysis of Tic3 as a High-Efficiency Anode for Calcium-Ion Batteries(Elsevier, 2024) Park, Jongee; Fatima, Syeda AfrinishA comprehensive analysis of the structural, electronic, and thermal properties of TiC3 has been conducted. The calculated thermal expansion coefficient throughout a significant portion of the temperature range leads to a negative value underscoring the material's significance. The carbon-rich polytype of titanium carbide (TiC3) is being proposed for the first time as an anode material for calcium-ion batteries (CIB). The adsorption of Ca2+ ions has been determined to be favorable, with high accommodation of guest atoms and sufficiently rapid ionic mobility. The total volume expansion for a maximum Ca2+ adsorbed TiC3 configuration is calculated to be 8.2 %, which is lower compared to other anode materials for CIBs. Through the calciation of TiC3 up to the highest Ca2+ concentration (Ca7TiC3), an exceptionally high theoretical capacity of 2236 mAh/g has been achieved. Regarding battery rate capability, the lowest diffusion barrier calculated is 0.13 eV, with a remarkably high diffusion coefficient along the corresponding pathway equal to 10-3 cm2/s, indicating the ease of Ca ion movement within the host material. Furthermore, the equilibrium distance (2.5 & Aring;) between our host and guest atoms indicates a robust interaction between them. These findings lay the groundwork for the development of high-performance anode materials for CIBs.Article Citation - WoS: 15Citation - Scopus: 17Kinetics of Co2 Capture by Carbon Dioxide Binding Organic Liquids: Experimental and Molecular Modelling Studies(Elsevier Sci Ltd, 2016) Orhan, Ozge Yuksel; Tankal, Hilal; Kayi, Hakan; Alper, ErdoganIn the scope of this work, new carbon dioxide binding organic liquids (CO(2)BOLs) were developed and kinetic parameters in terms of pseudo first-order rate constants for homogenous reaction between CO2 and CO(2)BOLs in 1-hexanol were obtained by using stopped-flow method with conductivity detection. As an amidine DBN (1,5-diazabicyclo[4.3.0]non-5-ene) and as a guanidine TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene) and BTMG (2-tert-butyl-1,1,3,3-tetramethylguanidine) were investigated. Experiments were performed by varying organic base (amidine or guanidine) weight percentage in 1-hexanol medium for a temperature range of 288-308 K. A modified termolecular reaction mechanism was used to analyse the experimental kinetic data. In addition, quantum chemical calculations by using B3LYP, MP2 and CCSD methods were performed to reveal the structural and energetic details of the single step termolecular reaction mechanism. Experimental and theoretical activation energies for these novel carbon dioxide capturing organic liquids were also unveiled. (C) 2016 Elsevier Ltd. All rights reserved.Article Citation - WoS: 8Citation - Scopus: 8The Investigation of Electronic Nature and Mechanical Properties Under Spin Effects for New Half-Metallic Ferromagnetic Chalcogenides Ag3crx4< (x = S, Se, and Te)(Elsevier, 2021) Erkisi, Aytac; Yildiz, Bugra; Wang, Xiaotian; Isik, Mehmet; Ozcan, Yusuf; Surucu, GokhanThis study presents the electronic and mechanical characteristics of ternary silver-based Ag3CrX4 (X = S, Se, and Te) chalcogenides having simple cubic crystalline structure (SC), conforming P4-3m (space group: 215) that are studied under the spin-polarized Generalized Gradient Approach (GGA) within the framework of the Density Functional Theory (DFT). The stable magnetic phase has been determined as the ferromagnetic (FM) phase for all studied systems. Then, phase stability, mechanical, thermal and electronic characteristics of Ag3CrX4 chalcogenides have been reported. In the calculated spin polarized electronic band structures for Ag3CrX4 chalcogenides, as an indicator of half-metallic behavior, metallicity has been observed in the majority spin channel, while indirect band gaps (1.04 eV for Ag3CrS4, 1.10 eV for Ag3CrSe4, and 1.25 eV for Ag3CrTe4) have been determined in the minority spin channel. Moreover, Ag3CrX4 chalcogenides have been found as thermodynamically stable and structurally synthesizable considering the calculated negative formation enthalpies. Elastic constants of studied chalcogenides satisfying Born-Huang criteria's pointed out the mechanical stability of materials. The predicted mechanical properties determined with elastic constants revealed that Ag3CrX4 chalcogenides belong to soft and ductile material family.
