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SIMULAC ~AO AB INITIO DE BASES NITROGENADAS INTERAGINDO COM NANOFITAS DE GRAFENO E SILICENO: PARAMETRIZAC ~AO E COMPARATIVO NOS DIFERENTES MATERIAIS

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Previous issue date: 2016-07-22 / In this thesis is studied the interaction between the nitrogenous bases, adenine,
cytosine, guanine and thymine with two nanostructures: the graphene and silicene
nanoribbons through ab initio calculations based on DFT (Density Functional Theory)
using the SIESTA (Spanish Initiative for Electronic Simulations with Thousands of
Atoms) software. Prior to implementing the software to simulate the behavior at the
atomic level of molecules all feature and variants was studied, for computer modeling and
simulation; which applications using nanostructures and the best spatial con guration
for construction of an initial parameter simulation. The nitrogenous bases as main
constitution of the genetic code component, in the form of a double trainer strand of
DNA, is the point of interest of this work, along with their behavior when the interaction,
by positioning the walking distance - with nanoribbons graphene and silicene. The
simulation of the nitrogenous bases and nanoribbons initially obey perpendicular position
with the atoms of forming hydrogen bonds in DNA, pointing to the nanostructures. It
was calculated, at the end of the simulations, the removal of nitrogenous bases of its
current initial position, the di erence in the values of total energy and charge transfer.
It has been shown that the interaction energy between nitrogenous bases and graphene
nanoribbon are thinner than those found for the interaction with the silicene nanoribbon.
When the nitrogenous bases are placed parallel to nanoribbons (both of graphene as
silicene) they present chemical bonds, while when they are arranged perpendicularly
to the surface of the material, they deviate in the course of its transverse path. It
also follows that the silicene nanoribbon is more stable in the adsorption energy than
nanoribbon graphene and the interaction of the bases is the energy bands that change
xiii
subtly, with respect of the gap values. For the graphene nanoribbon, the changes are
associated with the position of the Fermi level. These results show, in an original way,
di erent con gurations for the nitrogeneous basis on one dimensional carbon and silicon
materials. / Nessa tese e estudada a intera c~ao entre as bases nitrogenadas, adenina, citosina,
guanina e timina, com duas nanoestruturas: a nano ta de grafeno e a nano ta de
siliceno, atrav es de c alculos ab initio baseados na Teoria do Funcional da Densidade
(DFT), utilizando o software SIESTA (Spanish Initiative for Electronic Simulations
with Thousands of Atoms), esse programa computacional executa c alculos de estrutura
eletr^onica e simula c~oes ab initio de din^amica molecular de mol eculas e s olidos. Anterior
a execu c~ao do software para simular o comportamento a n vel at^omico das mol eculas, foi
estudada a caracter stica e variantes, para modelagem e simula c~ao computacional; quais
as aplica c~oes utilizando nanoestruturas e a melhor con gura c~ao espacial para constru c~ao
de um par^ametro inicial de simula c~ao. As bases nitrogenadas, sendo componente
principal da constitui c~ao do c odigo gen etico, na forma de um duplo lamento formador
do DNA (Deoxyribonucleic acid - Acido Desoxiribonucleico), e o ponto de interesse
deste trabalho, juntamente com seu comportamento quando na intera c~ao, atrav es do
posicionamento a pouca dist^ancia - com as nano tas de grafeno e siliceno. A simula c~ao
entre as bases nitrogenadas e as nano tas inicialmente obedecem um posicionamento
perpendicular com os atomos formadores das liga c~oes de hidrog^enio, no DNA, apontando
para as nanoestruturas. Foi calculado, ao nal das simula c~oes, o afastamento das bases
nitrogenadas da sua posi c~ao atual, a diferencia c~ao nos valores de energia total e a
respectiva transfer^encia de carga. Foi demonstrado que a energia de adsor c~ao entre as
bases nitrogenadas e a nano ta de grafeno s~ao mais t^enues do que aquelas encontradas
para a intera c~ao com a nano ta de siliceno. Quando as bases nitrogenadas s~ao colocadas
paralelas as nano tas (tanto de grafeno quanto de siliceno) elas fazem liga c~oes qu micas,
enquanto se forem dispostas perpendicularmente a superf cie do material, as mesmas se
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afastam no decorrer de seu trajeto transversal. Tamb em se conclui que a nano ta de
siliceno e mais est avel no sentido de energia de adsor c~ao do que a nano ta de grafeno e a
intera c~ao das bases faz as bandas de energia dessa, alterar de forma sutil, via mudan ca
no gap de energia. No caso da adsor c~ao na nano ta de grafeno observam-se altera c~oes
na posi c~ao do n vel de Fermi, sem mudan cas nas caracter sticas met alicas do sistema
original. Desta forma, este trabalho apresenta, de forma original, diferentes con gura c~oes
para a intera c~ao de bases nitrogenadas em sistemas unidimensionais de carbono e sil cio,
com aplica c~ao para a detec c~ao individual das bases nitrogenadas formadoras da mol ecula
de DNA.

Identiferoai:union.ndltd.org:IBICT/oai:tede.universidadefranciscana.edu.br:UFN-BDTD/570
Date22 July 2016
CreatorsMartins, Mirkos Ortiz
ContributorsFagan, Solange Binotto, Garcia, Vinícius Jacques, Rech, Virginia Cielo, Lara, Ivi Valentini, Rossato, Jussane
PublisherCentro Universitário Franciscano, Programa de Pós-Graduação em Nanociências, UNIFRA, Brasil, Biociências e Nanomateriais
Source SetsIBICT Brazilian ETDs
LanguagePortuguese
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis
Formatapplication/pdf
Sourcereponame:Repositório Institucional Universidade Franciscana, instname:Universidade Franciscana, instacron:UFN
Rightshttp://creativecommons.org/licenses/by-nc-nd/4.0/, info:eu-repo/semantics/openAccess

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