Ab Initio Method
Mostrando 1-12 de 87 artigos, teses e dissertações.
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1. RM1 Semiempirical Model: Chemistry, Pharmaceutical Research, Molecular Biology and Materials Science
In this review, we show improvements to the semiempirical quantum chemical method RM1 and present a wide range of its applications as reported by researchers of various areas, such as theoretical, organic, physical, analytical, and inorganic chemistry, as well as their interfaces with medicinal chemistry, biology, and materials science. Success of RM1 is see
J. Braz. Chem. Soc.. Publicado em: 2019-04
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2. Ab initio LSDA+U Study of Optical Properties of RVO4 (R = Eu, Ho, Lu) Compounds
A first principles investigation at the pressure 7 GPa of the optical properties of RVO4 (R= Eu, Ho, Lu) orthovanadates in the framework of the density functional theory (DFT) using the linearized-augmented plane-wave method is reported in order to predict new optical materials for continuous-wave lasers. The electronic structure of all orthovanadates is stu
Mat. Res.. Publicado em: 22/01/2018
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3. Thermodynamic study of asparagine and glycyl-asparagine using computational methods
This work aimed to develop an ab initio procedure for accurately calculating pKa values and applied it to study the acidity of asparagine and glycyl-asparagine. DFT methods with B3LYP composed by 6-31+G(d) basis set were applied for calculating the acidic dissociation constant of asparagine and glycyl-asparagine. The formation of intermolecular hydrogen bond
Braz. arch. biol. technol.. Publicado em: 2015-06
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4. Ab. initio study of the structural, elastic, electronic and optical properties of Cu3N
Electronic, optical, elastic, properties of Copper nitride (Cu3N) in cubic anti- ReO3 phase have been studied using the full-potential augmented plane waves (FP-LAPW) within density functional theory (DFT) framework. Generalized gradient approximation (GGA), local density approximation (LDA), Perdew - Burke - Ernzerhof generalized parameterization of gradien
Mat. Res.. Publicado em: 01/04/2014
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5. Experimental and ab initio data in the CALPHAD method: the Fe-Cr-Mo-C and Nb-Ni-Si systems. / Dados empíricos e ab initio no método CALPHAD: os sistemas Fe-Cr-Mo-C e Nb-Ni-Si.
O objetivo do presente projeto é a combinação de abordagens experimentais e teóricas para o desenvolvimento de bancos de dados termodinâmicos, visando o modelamento de aços e ligas de alto desempenho. Entre esses materiais estão as superligas fundidas por centrifugação para aplicações em fornos de reforma e pirólise, bem como aços-ferramenta ref
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/04/2012
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6. Caracterização estrutural e eletrônica da zircônia pura e com defeitos e impurezas / Structural and electronic characterization of zirconia, pristine and with impurities
In this investigation we studied the electronic properties and the structural stabilities of zirconia (ZrO2), as well as oxygen vacancy and Ce substitutional impurity. The investigations were carried by computational simulations using ab initio methods, based on the density functional theory and the APW + lo (Aumengted Plane Waves plus local orbitals) method
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/12/2011
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7. PREFERRED SUBSTITUTION SITES FOR CD AND SR IN HYDROXYAPATITE: THEORETICAL PREDICTION BASED ON A SEMI-EMPIRICAL TIGHT-BINDING METHOD / SÍTIOS PREFERENCIAIS DE SUBSTITUIÇÃO DE CD E SR EM HIDROXIAPATITA: PREVISÃO TEÓRICA BASEADA EM MÉTODOS DE LIGAÇÃO FORTE, HUCKEL ESTENDIDO
A hidroxiapatita (HA) é um constituinte natural dos ossos e rochas ígneas e tem grande importância na reserva de cálcio e fósforo dos vertebrados. Possui propriedades de biocompatibilidade e bioatividade, permitindo que haja substituições de seus átomos por outros. Neste trabalho são estudadas as substituições de Cd e Sr nos dois sítios cristalin
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/09/2011
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8. Mecanismo da decomposição e reações com radicais em acetatos / Decomposition mecanism and radical reactions with acetates
Computational studies on methyl and ethyl acetates molecules using ab initio and density functional calculations exploring the unimolecular mechanism, induced by multiphoton absorption, and the bimolecular reactions with OH and Cl radicals, have been performed in this work. Analysis of the calculated energy barriers and rate constants of unimolecular reactio
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/05/2011
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9. Ab Initio calculations of interactions betweeen Cd and nitrogenous bases o DNA / Cálculos ab initio de interações entre Cd e bases nitrogenadas do DNA
As interações hiperfinas são uma ótima ferramenta para estudar um sítio específico e obter informações importantes sobre o sistema. No presente trabalho analisamos de forma teórica as propriedades eletrônicas, estruturais e hiper nas do Cádmio (Cd) ligado às bases nitrogenadas do DNA. A motivação surgiu da colaboração com o grupo do prof. Art
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/05/2011
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10. Cálculo de propriedades elétricas lineares, não-lineares e estruturais da molécula HOBr
Ab initio, also known as first principles, computational methods are highly esteemed because of the accuracy of the results produced and the fact that they are not built upon any empirical models, therefore considered reliable. Although, these positive remarks carry along a heavy computational effort, which increase very rapidly with the number of basis func
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/04/2010
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11. Modeling elastic and thermal properties of 2.5D carbon fiber and carbon/SiC hybrid matrix composites by homogenization method
Abstract: Advanced carbon fiber hybrid carbon-ceramic matrix composites are realizing their potential in many thermostructural components for aerospace vehicles. This work presents ab-initio predictions of elastic constants and thermal properties for 2.5D carbon fiber reinforced carbon-silicon carbide hybrid matrix composites, by using the homogenization tec
J. Aerosp. Technol. Manag.. Publicado em: 2010-08
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12. Abordagem da química das fragrâncias de almíscares por estudos teóricos e espectroscópicos
Both pentadecanolide and exaltolide compounds were widely used by the perfume industry for their soft and persistent odor of musks, with high fixative power. However, once they have animal origin (customarily found in anal glands of the musk deer), their usage is controlled by high costs and, also, by environmental activist groups and by all animal lovers. A
Publicado em: 2010