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Showing 1 to 20 of 91 for “"B3LYP"”.
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Reaktive organische und anorganische Systeme mit Gruppe 14 Elementen: eine computerchemische Analyse
… of Si4R6 and Ge4R6 isomers is performed with B3LYP/6-31G(d). The results show a great influence of the substituent R on the relative energies of these isomers. The addition of germylenes to diacetylenes can result in two products. Depending on the substituents at the carbene analogon the …
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Computational Studies of Protonated Cyclic Ethers and Benzylic Organolithium Compounds
… 2-methyl-1,2-epoxypropane were performed at the B3LYP and MP2 levels (both with the 6-311++G** basis set). Structural analyses were performed for 10 protonated epoxides using B3LYP, MP2, and CCSD/6-311++G** calculations. Protonated 2-methyl-1,2-epoxypropane was the most problematic species …
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Weak interactions and excited states from Coulomb-attenuated DFT
… functionals, such as the ubiquitous B3LYP, provide reasonable accuracy, but their continued use is increasingly based on the collective experience with the functional that has been accumulated, rather than the results that can be achieved. This thesis considers the circumstances under …
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Thermochemistry and bond energies of acetohydrazide, amides and cyclic alkyl ethers
… energies were calculated using the DFT methods B3LYP/6-31G(d,p), B3LYP/6-31G(2d,2p) and the composite CBS-QB3 methods employing a series of work reactions to further improve accuracy of the [Delta]H_f (298K). Molecular structures, vibration frequencies and internal rotor potentials were …
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Experimentelle und theoretische Studien zur Einsetzbarkeit von Carbokationen in der organischen Synthese
… mit dem Methylanion (XC6H4)2CH-CH3 wurden auf B3LYP/6-31G(d,p)-Niveau optimiert. Struktur und Reaktivität wurden diskutiert. ClClMeMeMeMeOOOOONMe2Me2NNNNNtol(Ph)CH+(tol)2CH+(ani)2CH+(pcp)2CH+ani(Ph)CH+ani(tol)CH+(fur)2CH+(mfa)2CH+(dma)2CH+(jul)2CH+(lil)2CH+Ph2CH+NNCF3MeMeF3COH3CH3CCH3H3C …
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Computational Studies on Group 14 Elements (C, Si and Ge) in Organometallic and Biological Compounds.
… with different organometallic fragments at B3LYP and B3P86 level reveal a reverse charge transfer from ligand to metal in Si and Ge complexes whereas in C complexes there is a small charge transfer from metal to ligand. The H-bridged complexes are more stable than the complexes based on …
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Thermochemical properties, bond energies and internal rotor potentials in methyl ethyl sulfide and oxygenated sulfur hydrocarbons intermediates for modeling its combustion and atmospheric chemistry
… energy are determined using Density Functional B3LYP/6-31G (d,p) and B3LYP/6-31+G(2d,p) together with the higher level composite CBS-QB3. Enthalpies of formation (Hf) for stable species are calculated in the levels of B3LYP/6-31G (d,p), B3LYP/6-31+G(2d,p) and CBS-QB3 using work reactions that …
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Development of pharmacophore and comfa study of rigid and flexible sigma 2 receptor ligands
… AM1, ab initio HF/6-31G* and density functional B3LYP/6-31G* in Gaussian 98. The pharmacophore model was derived by using Distance Comparisions (DISCOtech) from 4 partially to highly active 62 receptor ligands. The Comparative Molecular Field Analysis (CoMFA) was developed for 22 bioactive 62 …
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Thermochemistry and kinetic analysis on radicals of acetaldehyde + O2, allyl radical + O2 and diethyl and chlorodiethyl sulfides
… frequencies obtained at the HF/6-31G(d') or B3LYP/6-31G(d,p) level of theory. Internal rotor contributions are included in calculation of entropy, S _{298}, and heat capacities, Cp(T). Rate constants are estimated as a function of pressure and temperature using multifrequency quantum …
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Estudios teóricos experimentales sobre la estructura de amidas y proteínas
… geométricos, proporcionados por cálculos DFT (B3LYP/6-31G*).
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Tautomería y reactividad de 2-alquiltioisomünchnonas
… Results have been rationalized through DFT (B3LYP/6-31G*) calculations.
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Kinetics of HO2 abstraction of H atoms from hydrocarbons and thermochemical properties of urethane monomers and radicals
… vibrational frequencies are determined at the B3LYP/6-3111G(d,p) density functional level. The S _{298} and C_p(T) values (300<=T/K<=1500) from vibrational, translational, and external rotational contributions are calculated using statistical mechanics based on the vibrational frequencies and …
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Thermochemistry and bond energies of nitro -alkanes, -alkenes, -carbonyls and corresponding nitrites
… (10K T 5 5000K) are calculated at the individual B3LYP/6-31G(d,p), B3LYP /6-31+G(2d,2p) and composite CBS-QB3 levels. Potential energy barriers for the internal rotations have been computed at the B3LYP/6-31G(d, p) level of theory and the lower barrier contributions are incorporated into entropy …
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Towards Combined Computational and Experimental Studies on Toxicity of Silver Nanoparticles
… species that occur experimentally and by using B3LYP the best density functional in predicting the HOMO, LUMO and ΔEgap of CP-PAHs with overall MAE of 014 eV. The best absorption spectra otef CP-PAHs were predicted using B3LYP for geometry optimizations followed by TD-CAMB3LYP with MAE of 29 nm. …
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Enzyme-Catalyzed Phosphoryl Transfer Reactions: Energetics of Transition States and Vanadate Analogues in Aqueous Solution
… dimethyl ester have been calculated using the B3LYP/TZVP density functional quantum chemical methods, and the polarized continuum (PCM) and Langevin dipoles (LD) solvation models. These calculations were carried out to obtain fundamental information on the ability of vanadate esters to function …
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Development of Property Prediction Methods for Sodium-ion Battery Electrolytes
… (DMC) and ethylene carbonate (EC). A larger B3LYP/6-311++G** basis set was used to optimize the geometry and compute the vibrational spectrum of a single molecule EC and its complex including the sodium cation as a benchmark. Both the efficiency and accuracy of ab initio calculations were …
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Propriedades eletrônicas, estruturais e espectroscópicas de diazocetonas através de cálculos quânticos e estudos in silico das ligações realizadas pela molécula de amurensinina no sítio de ligação do receptor específico de N-metil-D-Aspartato (NMDA)
… foram otimizados utilizando o método DFT/B3LYP/6-311G+(d,p) e suas estruturas e propriedades foram analisadas, como valores de comprimento de ligação, ângulos de ligação, energia, momento dipolo, HOMO e LUMO e superfície de potencial eletrônico. Os espectros de RMN 1H e 13C foram …
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Experiment, thermodynamic properties and modeling on combustion of methyl tert-butyl ether : isobutane and isobutene and thermodynamic properties of chloro alkanes and alkenes
… (CBS-4 and CBS-q with MP2(full)/6-31g(d) and B3LYP/6-31g(d) optimized geometries), density functional (B3LYP/631g(d)), semi-empirical MOPAC (PM3) molecular orbital calculations, and by group additivity estimation. Thermochemical kinetic parameters are developed for each elementary reaction …
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Comparison of Calculated Normal Mode Molecular Vibrations with Experimental Gas-Phase Infrared Spectroscopy
… methods (theories and basis sets), such as, B3LYP-D/cc-pVDZ, MP2-cc-pVDZ, CCSD/cc-pVDZ, CCSD(T)/aug-cc-pVDZ, CCSD(T)/aug-cc-pVTZ, CCSD/cc-pVDZ and CCSD/cc-pVTZ on different diatomic and polyatomic molecules using the <em>ab initio</em> computational software package, Psi4. H<sub>2</sub>, …
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Mechanisms of Methoxide Ion Substitution and Acid- Catalyzed Z/E Isomerization of N-Methoxyimines
… (HF/6-31+G*, MP2/6-31+G*//HF/6-31+G*, B3LYP/6- 31+G*//HF/6-31+G*, HF-SCIPCM/6-31+G*//HF/6-31+G*) were performed to define the reaction surface. These calculations demonstrate a relatively large barrier for nucleophilic attack in relation to halogen loss and support the experimental …
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