Dissertations / Theses on the topic 'Intermolecular forces'
To see the other types of publications on this topic, follow the link: Intermolecular forces.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Intermolecular forces.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Bianchini, Thiago Bufeli [UNESP]. "O ensino por investigação abrindo espaços para a argumentação de alunos e professores do ensino médio." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/90983.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:24:50Z (GMT). No. of bitstreams: 0
Previous issue date: 2011-09-28Bitstream added on 2014-06-13T19:52:39Z : No. of bitstreams: 1
bianchini_tb_me_bauru.pdf: 683609 bytes, checksum: ef65f80c6217a55d4db4bb22436bf15c (MD5)Nas últimas décadas, o Ensino de Ciências vem buscando estratégias que favoreçam o entendimento dos conteúdos científicos ou, como indica Driver (1999), a enculturação da Ciência (DRIVER, CAPECCHI E CARVALHO, MORTIMER, 2000), além da formação de alunos e professores críticos e reflexivos. O uso da argumentação em salas de aula pode se tornar grande aliada na formação de jovens pensadores e críticos, que consigam utilizar seus pensamentos em favor próprio e em conjunto, que sejam capazes de discutir problemas e propor soluções, não apenas na escola, mas em seu dia a dia. Para favorecer a argumentação, foi utilizado um minicurso investigativo com o tema Forças intermoleculares. Nossa proposta de trabalho procurou investigar quais são as potencialidades do uso integrado desses referenciais teóricos e qual a contribuição de uma proposta de minicurso invesetigativo no desenvolvimento de habilidades de argumentação em alunos e futuros professores além de analisar a proposta investigativa utilizada. Os dados analisados foram divididos em três categorias, i) a proposta do minicurso investigativo com base na classificação de atividades de ensino proposta por Canal (2000), ii) a qualidade da argumentação com Osborne et al (2004) e iii) a atuação do professor na elaboração dos argumentos dos alunos com Mendonça e Justil (2009). Os resultados mostram que a atividade proposta favoreceu a argumetnação dos alunos e professores, possibilitando a abertura de espaços na sala de aula para que ocorra diálogo entre os alunos e os professores. Pode-se perceber o papel fundamental do professor na elaboração dos argumentos dos alunos, pois, se os mesmos não direcionarem as discussões, os argumentos podem ser mal elaborados ou mal explorados
In recent decades, the Teaching if Science has been searching for strategies that enhance the understanding of scientific content or, as indicated by Driver (1999), enculturation of Science (DRIVER, Capecchi and CARVALHO, MORTIMER, 2000) and the training of teachers ans students to be critical and reflective. The use of argumentation in the classroom can become a great ally in forming young thinkers and critics, who can use their own behalf and thoughts together; they can discuss problems and propose solutions, not just in shool but in their day by day. To facilitate the argument we used an investigate shor course with the theme Intermolecular Forces. Our proposal of work aimed to investigate what are the potential use of integrated theoretical and the contribution of a proposed short course in the development of investigate reasoning abilities in students and future teachers as well as used to analyze the research proposal. Data were divided into three categories, i) the proposed investigative mini course based on the classification of educational activities proposed by Canal (2000), ii) the quality of argumentation with Osborne et al (2004) and iii) the performance of teacher in preparing students with the arguments of Mendonça and Justi (2009). The results show that the proposed activity favored the argument of the students and teachers, enabling the opening of spaces in the classroom dialogue to occur between students and teachers. It can be noticed the teqacher's role in the development of students arguments, because if they do not guiding discussions arguments can be poorly designed or poorly explored
2
Bianchini, Thiago Bufeli. "O ensino por investigação abrindo espaços para a argumentação de alunos e professores do ensino médio /." Bauru : [s.n.], 2011. http://hdl.handle.net/11449/90983.
Full textAbstract:
Orientador: Silvia Regina Quijadas Ara ZulianiBanca: Maria Eunice Ribeiro Marcondes
Banca: Odete Pacubi Baierl Teixeira
Resumo: Nas últimas décadas, o Ensino de Ciências vem buscando estratégias que favoreçam o entendimento dos conteúdos científicos ou, como indica Driver (1999), a enculturação da Ciência (DRIVER, CAPECCHI E CARVALHO, MORTIMER, 2000), além da formação de alunos e professores críticos e reflexivos. O uso da argumentação em salas de aula pode se tornar grande aliada na formação de jovens pensadores e críticos, que consigam utilizar seus pensamentos em favor próprio e em conjunto, que sejam capazes de discutir problemas e propor soluções, não apenas na escola, mas em seu dia a dia. Para favorecer a argumentação, foi utilizado um minicurso investigativo com o tema "Forças intermoleculares". Nossa proposta de trabalho procurou investigar quais são as potencialidades do uso integrado desses referenciais teóricos e qual a contribuição de uma proposta de minicurso invesetigativo no desenvolvimento de habilidades de argumentação em alunos e futuros professores além de analisar a proposta investigativa utilizada. Os dados analisados foram divididos em três categorias, i) a proposta do minicurso investigativo com base na classificação de atividades de ensino proposta por Canal (2000), ii) a qualidade da argumentação com Osborne et al (2004) e iii) a atuação do professor na elaboração dos argumentos dos alunos com Mendonça e Justil (2009). Os resultados mostram que a atividade proposta favoreceu a argumetnação dos alunos e professores, possibilitando a abertura de espaços na sala de aula para que ocorra diálogo entre os alunos e os professores. Pode-se perceber o papel fundamental do professor na elaboração dos argumentos dos alunos, pois, se os mesmos não direcionarem as discussões, os argumentos podem ser mal elaborados ou mal explorados
Abstract: In recent decades, the Teaching if Science has been searching for strategies that enhance the understanding of scientific content or, as indicated by Driver (1999), enculturation of Science (DRIVER, Capecchi and CARVALHO, MORTIMER, 2000) and the training of teachers ans students to be critical and reflective. The use of argumentation in the classroom can become a great ally in forming young thinkers and critics, who can use their own behalf and thoughts together; they can discuss problems and propose solutions, not just in shool but in their day by day. To facilitate the argument we used an investigate shor course with the theme "Intermolecular Forces". Our proposal of work aimed to investigate what are the potential use of integrated theoretical and the contribution of a proposed short course in the development of investigate reasoning abilities in students and future teachers as well as used to analyze the research proposal. Data were divided into three categories, i) the proposed investigative mini course based on the classification of educational activities proposed by Canal (2000), ii) the quality of argumentation with Osborne et al (2004) and iii) the performance of teacher in preparing students with the arguments of Mendonça and Justi (2009). The results show that the proposed activity favored the argument of the students and teachers, enabling the opening of spaces in the classroom dialogue to occur between students and teachers. It can be noticed the teqacher's role in the development of students arguments, because if they do not guiding discussions arguments can be poorly designed or poorly explored
Mestre
3
Gellert, P. R. "Spectroscopic and theoretical studies of intermolecular forces." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234945.
Full text
4
Al-Rasoul, Khalid. "Intermolecular forces in amphiphiles : an emulsion stability problem." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.256365.
Full text
5
Zarari, Maria Prodromou. "Intermolecular forces from the speed of sound in gases." Thesis, Imperial College London, 1993. http://hdl.handle.net/10044/1/8828.
Full text
6
Jiemchooroj, Auayporn. "First-principles calculations of long-range intermolecular dispersion forces." Licentiate thesis, Linköping : Dept. of Electrical Engineering, Linköping University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7512.
Full text
7
Robertson, Rae Marie. "Single-molecule studies of DNA dynamics and intermolecular forces." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3284227.
Full textAbstract:
Thesis (Ph. D.)--University of California, San Diego, 2007.Title from first page of PDF file (viewed January 11, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 139-149).
8
Chatten, Ryan. "The effect of intermolecular forces on diffusion in polymers." Thesis, Brunel University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393176.
Full text
9
Jones, Andrew. "Quantum drude oscillators for accurate many-body intermolecular forces." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4878.
Full textAbstract:
One of the important early applications of Quantum Mechanics was to explain the Van-der-Waal’s 1/R6 potential that is observed experimentally between two neutral species, such as noble gas atoms, in terms of correlated uncertainty between interacting dipoles, an effect that does not occur in the classical limit [London-Eisenschitz,1930]. When many-body correlations and higher-multipole interactions are taken into account they yield additional many-body and higher-multipole dispersion terms. Dispersion energies are closely related to electrostatic interactions and polarisation [Hirschfelder-Curtiss-Bird,1954]. Hydrogen bonding, the dominant force in water, is an example of an electrostatic effect, which is also strongly modified by polarisation effects. The behaviour of ions is also strongly influenced by polarisation. Where hydrogen bonding is disrupted, dispersion tends to act as a more constant cohesive force. It is the only attractive force that exists between hydrophobes, for example. Thus all three are important for understanding the detailed behaviour of water, and effects that happen in water, such as the solvation of ions, hydrophobic de-wetting, and thus biological nano-structures. Current molecular simulation methods rarely go beyond pair-wise potentials, and so lose the rich detail of many-body polarisation and dispersion that would permit a force field to be transferable between different environments. Empirical force-fields fitted in the gas phase, which is dominated by two-body interactions, generally do not perform well in the condensed (many-body) phases. The leading omitted dispersion term is the Axilrod-Teller-Muto 3-body potential, which does not feature in standard biophysical force-fields. Polarization is also usually ommitted, but it is sometimes included in next-generation force-fields following seminal work by Cochran [1971]. In practice, many-body forces are approximated using two-body potentials fitted to reflect bulk behaviour, but these are not transferable because they do not reproduce detailed behaviour well, resulting in spurious results near inhomogeneities, such as solvated hydrophobes and ions, surfaces and interfaces. The Quantum Drude Oscillator model (QDO) unifies many-body, multipole polarisation and dispersion, intrinsically treating them on an equal footing, potentially leading to simpler, more accurate, and more transferable force fields when it is applied in molecular simulations. The Drude Oscillator is simply a model atom wherein a single pseudoelectron is bound harmonically to a single pseudonucleus, that interacts via damped coulomb interactions [Drude,1900]. Path Integral [Feynman-Hibbs,1965] Molecular Dynamics (PIMD) can, in principle, provide an exact treatment for moving molecules at finite temperature on the Born- Oppenheimer surface due to their pseudo-electrons. PIMD can be applied to large systems, as it scales like N log(N), with multiplicative prefactor P that can be effectively parallelized away on modern supercomputers. There are other ways to treat dispersion, but all are computationally intensive and cannot be applied to large systems. These include, for example, Density Functional Theory provides an existence proof that a functional exists to include dispersion, but we dont know the functional. We outline the existing methods, and then present new density matrices to improve the discretisation of the path integral. Diffusion Monte Carlo (DMC), first proposed by Fermi, allows the fast computation of high-accuracy energies for static nuclear configurations, making it a useful method for model development, such as fitting repulsion potentials, but there is no straightforward way to generate forces. We derived new methods and trial wavefunctions for DMC, allowing the computation of energies for much larger systems to high accuracy. A Quantum Drude model of Xenon, fit in the gas-phase, was simulated in the condensed-phase using both DMC and PIMD. The new DMC methods allowed for calculation of the bulk modulus and lattice constant of FCC-solid Xenon. Both were in excellent agreement with experiment even though this model was fitted in the gasphase, demonstrating the power of Quantum Drudes to build transferable models by capturing many-body effects. We also used the Xenon model to test the new PIMD methods. Finally, we present the outline of a new QDO model of water, including QDO parameters fitted to the polarisabilities and dispersion coefficients of water.
10
Monari, Antonio <1976>. "Ab initio computation of electric properties and intermolecular forces." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/468/1/tesi.pdf.
Full text
11
Monari, Antonio <1976>. "Ab initio computation of electric properties and intermolecular forces." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/468/.
Full text
12
Gu, Yi Qi. "Intramolecular [2+2] Cycloadditions of Phenoxyketenes and Intermolecular [2+2] Cycloadditions of Aminoketenes." Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc332334/.
Full textAbstract:
One objective of this study was to explore the intramolecular [2+2] cycloadditions of phenoxyketenes to carbonyl groups with isoflavones and benzofurans as target compounds. The other objective was to investigate the eyeloaddition reactions of rarely studied aminoketenes.
The conversion of 2-(carboxyalkoxy)benzils to the corresponding phenoxyketenes leads to an intramolecular [2+2] cycloaddition to ultimately yield isoflavones and/or 3-aroylbenzofurans. The product distributions are dependent upon the substitution pattern in the original benzil acids. The initial cycloaddition products, β-lactones, are isolated in some instances while some β-lactones spontaneously underwent decarboxylation and could not be isolated.
The ketene intermediate was demonstrated in the intramolecular reaction of benzil acids or ketoacids with sodium acetate and acetic anhydride. It is suggested that sodium acetate and acetic anhydride could serve as a source for the generation of ketenes directly from certain organic acids. The treatment of ketoacids with acetic anhydride and sodium acetate provides a simpler procedure to prepare benzofurans than going through the acid chloride with subsequent triethylamine dehydrochlorination to give the ketenes.
N-Ary1-N-alkylaminoketenes were prepared for the first time from the corresponding glycine derivatives by using p-toluenesulfonyl chloride and triethylamine. These aminoketenes underwent in situ cycloadditions with cyclopentadiene, cycloheptene and cyclooctenes to yield only the endo -bicyclobutanones. The cycloheptene and cyclooctene cycloaddition products underwent dehydrogenation under the reaction conditions to yield bicycloenamines. A mechanism is proposed for this dehydrogenation involving a radical cation of the arylalkylamine. (N-Phenyl-N-methyl) aminomethylketene was also prepared and found to undergo an intramolecular Friedel-Crafts type acylation to yield an indole derivative when prepared by the acetic anhydride, sodium acetate method.
The in situ cycloaddition of N-aryl-N-alkyl aminoketenes with various imines was found to form predominately cis-3-amino-2-azetidinones. A mechanism involving a dipolar intermediate is provided whereby the structure of the intermediate is determined by both electronic and steric effects. The stereochemistry of the resulting β-lactams is dependent upon the structure of the dipolar intermediate.
13
Allen, Stephanie. "The study of biomolecular interactions using scanning probe microscopy." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363596.
Full text
14
Murdachaew, Garold. "Accurate ab initio intermolecular potentials with a focus on monomer flexibility." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 5.40 Mb., 293 p, 2005. http://wwwlib.umi.com/dissertations/fullcit/3182189.
Full text
15
Curran, Adrienne Rachael. "Intermolecular forces in lipid bilayers modulate the folding of bacteriorhodopsin." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321892.
Full text
16
Dean, Delphine Marguerite Denise 1978. "Modeling and measurement of intermolecular interaction forces between cartilage ECM macromolecules." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30153.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 143-151).
The mechanical properties of cartilage tissue depend largely on the macromolecules that make up its extracellular matrix (ECM). Aggrecan is the most abundant proteoglycan in articular cartilage. It is composed of a core protein with highly charged, densely packed glycosaminoglycan (GAG) side chains, which are responsible for [approximately] 50% of the equilibrium compressive stiffness of the tissue. Using atomic force microscopy (AFM) and high resolution force spectroscopy (HRFS), it is now possible to directly measure nanoscale interactions between ECM macromolecules in physiologically relevant aqueous solution conditions. In order to interpret these data and compare them to macroscopic tissue measurements, a combination of experiments and theoretical modeling must be used. In this thesis, a new molecular-scale continuum Poisson-Boltzmann (PB)-based model was developed to predict the intermolecular interactions between GAG macromolecules by taking into account nanoscale space varying electric potential and fields between neighboring GAGs. A rod-like charge density distribution describing the time averaged space occupied by a single GAG chain was formulated. The spacing and size of the rods greatly influenced the calculated force even when the total charge was kept constant. The theoretical simulations described HRFS experimental data of the normal interaction force between two surfaces chemically end-grafted with an array of GAGs ("brushes") more accurately than simpler models which approximate the GAG charge as a homogeneous volume or planar surface charge. Taken together, these results highlight the importance of nonuniform molecular-level charge distribution on the measured GAG interaction forces. Normal interaction forces between aggrecan macromolecules were measured using contact mode AFM imaging and by HRFS.
(cont.) The aggrecan molecules were end-grafted to gold-coated substrates and probe tips to achieve brush-like layers at physiologically relevant densities. Both colloidal probe tips (2.5[micro]m radius) and sharper probe tips ([approximately] 25-50nm radius) were used. The measured normal forces were predominantly repulsive and showed a strong ionic strength dependence reflecting the importance of repulsive electrostatic interactions. These aggrecan-aggrecan forces were much larger than those previously measured between brushes composed only of a single layer of GAG chains isolated from aggrecan molecules. The measured aggrecan normal force interactions were then compared to the predictions of the PB charged rod model for GAG electrostatic interactions and to measurements of the equilibrium compressive modulus of intact cartilage tissue. At near physiological bath conditions (0.1M NaCl), the PB electrostatic model closely predicted the values of the measured force for nanomechanical strains < 0.4, using model parameter values that were all fixed to their known values from the literature. At higher strains, the measured normal forces were higher than those predicted by the model, qualitatively consistent with the likelihood that other nonelectrostatic interactions were becoming more important. A compressive stiffness was also calculated from the measured aggrecan-aggrecan nanomechanical force data, and was found to be [approximately] 50% of the modulus of native intact cartilage. This is consistent with previous reports suggesting that aggrecan-associated electrostatic interactions account for approximately half of the tissue modulus.
by Delphine Marguerite Denise Dean.
Ph.D.
17
Reid, Suazette N. "Synthetic stratergies [sic] towards a diureidocalix[4]arene." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4961.
Full textAbstract:
Self-organization is a common occurrence among molecules in nature and questions of how and why these molecules interact and come together by intermolecular forces has been under investigation by those interested in molecular recognition. Synthetic molecules able to mimic nature have become important in the area of supramolecular chemistry. Calixarenes are a group of molecules that is being investigated for their ability to self-assemble into dimeric capsules. Such capsules can be very useful for catalysis, molecular recognition and for encapsulation. The synthetic stratergies involved in the synthesis of a diureidocalix[4]arene is presented. In this case the taget molecule is a tetrapropylcalix[4]arene substituted on the upper rim with two urea groups separated by a hydrocarbon chain will be synthesized. This molecule can then be used to investigate its dimerization properties.
18
RENDINE, STEFANO. "MODELLING INTERMOLECULAR FORCES IN BIOMOLECULES: FROM PROTEIN-PROTEIN INTERACTIONS TO HALOGEN BONDS." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/167913.
Full textAbstract:
The accurate description and evaluation of the intermolecular interactions has a great importance in the molecular modelling of biological systems.
Protein-protein interactions, in particular, being involved in virtually every cellular process, are nowadays the object of thorough studies aimed at the understanding and modulation of the underlying mechanism. In the Part I of the present work, it will be shown how, through a computational approach, it is possible to get an in-depth analysis of the network of interactions occurring at the interface between tubulin subunits and how vinblastine, a commonly used anticancer agents, is able to interfere with the correct protein association, so having a therapeutic effect. In the Part II, the self-association of the bacterial protein FtsZ will be studied, showing that the detailed description of the protein-protein interactions can provide key information for the de-novo design of inhibiting molecules.
Finally, in the Part II, the attention will be focused on the computational study of halogen bonding, which is found to have a great relevance in the recognition process between biological macromolecules and halogenated agents. In particular, it will be shown that a specific approach is mandatory for its correct description in the framework of the classical force-fields.
19
Jiemchooroj, Auayporn. "Long-range intermolecular dispersion forces and circular dichroism spectra from first-principles calculations." Doctoral thesis, Linköping : Department of Physics, Chemistry and Biology, Linköpings universitet, 2007. http://www.bibl.liu.se/liupubl/disp/disp2007/tek1118s.pdf.
Full text
20
Syvitski, Raymond Thomas. "Probing anisotropic intermolecular forces in nematic liquid crystals using NMR and computer simulations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0016/NQ48727.pdf.
Full text
21
Cao, Bei, and 曹蓓. "Development of polarizable water models." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2015. http://hdl.handle.net/10722/211115.
Full textAbstract:
Polarization plays a significant role in the physical and chemical properties of water, thus polarizable water models have been extensively evolved and studied in the past several decades. In this dissertation, two polarizable water models have been extended, and some physical properties in gas phase and condensed phase were studied and analyzed. It was verified that the out-of-plane polarization effect is of great importance in some physical properties. Besides, we proved that there are some connections between these two models, although they were derived from different methodologies.
The first polarizable water model we developed was a combination of charge response kernel (CRK) method and polarizable point dipole (PPD) method. In the CRK method, a CRK matrix is defined as the second order derivative of energy with respect to the external potential at atomic sites. It is applied to represent the intensity of charge response to external environment. While in the PPD method, the polarizability tensor which is the second order derivative of energy with respect to external field at the same site, is introduced to characterize the variation of dipole moment in the presence of external perturbation. In our method, we proved that although the CRK matrix of three-site water model has 9 element, it only carries two independent variables, and these two variables only rely on the water geometry and the in-plane polarizability. Thus besides the CRK matrix located on each atomic site, an additional polarizability residing on oxygen atom specifically inducing dipole moment along the direction perpendicular to the water plane was added in our model. With the addition of the out-of-plane description, some physical properties were much enhanced.
In the second polarizable water model we extended, electronegativity equalization (EE) method was employed. In this three-site water model, atomic electronegativity and hardness matrix were the first and second order derivative of energy with respect to the partial charge on atomic sites, respectively. In this method, electronegativity differs among different atom types, and the off-diagonal elements in hardness matrix are related on not only atom types but also distances among the corresponding atoms. Accordingly, the intramolecular water deformation can be included. Thus flexible polarizable water model is accessible. With flexibility, this water model is more realistic. Our model validated that more flexible parameterization and geometry could improve the physical performance. At last, we connected the second polarizable water model with the first one. Although the two polarizable models were derived from different methodologies, we proved that under one simple approximation, corresponding CRK matrix can be achieved from hardness matrix.published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
22
Fedor, Anna M. "Terahertz spectroscopy of the intermolecular and intramolecular vibrations of molecules in solution." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available, full text:, 2007. http://wwwlib.umi.com/cr/syr/main.
Full text
23
Omnes, Laurent. "Towards the biaxial nematic phase via specific intermolecular interactions." Thesis, University of Exeter, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368368.
Full text
24
Odendal, James Arthur. "Investigating intermolecular interactions motifs in ammonium carboxylate salts." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2965.
Full textAbstract:
Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: This thesis reports an in-depth investigation of the intermolecular interaction motifs in secondary, primary and ammonium carboxylate salts. The investigation was conducted using the Cambridge Structural Database (CSD), together with a systematic steric-specific experimental study. The tendency in the literature has been to analyse organic salt crystal structures in terms of hydrogen bonding patterns, almost ignoring cation-anion interactions. This study focuses on the cation-anion interactions in secondary, primary and ammonium carboxylate salts, which have a direct effect on the formation of specific structural motifs. The ideas of ring-stacking and ring-laddering, which arise from the tendency of cations and anions to arrange themselves so as to maximise electrostatic interactions, have been applied to ammonium carboxylate salts. An extensive survey of organic ammonium carboxylate salt structures in the CSD has been carried out. The structural motifs in ammonium carboxylates were investigated, and a set of predictive rules for the pattern of intermolecular interactions in these salts was developed. Using these results, the formation of ring-stacking or ring-laddering in primary ammonium carboxylate salts can be predicted. The results from the CSD survey are discussed in Chapter 3. An experimental study has been carried out, which complements the results obtained from the CSD survey. The experimental study formed 19 novel ammonium carboxylate salts, of which 2 formed hydrates and 2 co-crystals of salts. The experimental results confirm what was found in the CSD survey, and this is discussed in Chapter 4. This study has found that the principle of ring-stacking and ring-laddering can be applied in a general form to the crystal structures of organic ammonium carboxylate salts. The size of the cation and the anion in these salts has a significant effect on the formation of structural motifs in the solid state. Interactions between cation and anion substituents also play an important role in the formation of particular structural motifs in ammonium carboxylate salts.
AFRIKAANSE OPSOMMING: In hierdie tesis word die intermolekulêre interaksie motiewe in die sekondêre, primêre en ammonium karbosilaat soute in-diepte ondersoek. Die studie is gedoen met behulp van die Cambridge Strukturele Databasis (CSD), saam met ‟n sistematiese steriesspesifieke eksperimentele studie. Die neiging in die literatuur is om organiese sout kristal strukture in terme van waterstofbindings patrone te analiseer sonder om katioon-anioon interaksies in ag te neem. Die studie fokus juis op hierdie katioon-anioon interaksies tussen sekondêre, primêre en ammonium karbosilaat soute wat ‟n direkte effek het op die vorming van spesifieke strukturele motiewe naamlik „ring-stacking‟ en „ring-laddering‟ wat hul oorsprong kry vanaf die neiging van katione en anione om hulself op so ‟n wyse te rangskik sodat die elektrostatiese interaksies ‟n maksimum kan bereik, op die ammonium karboksilaat soute. ‟n Volledige ondersoek van ammonium karboksilaat soute in die CSD is gedoen. Die strukturele motiewe in ammonium karboksilaat is ondersoek, en ‟n stel reels wat die patrone van intermolekulêre interaksies in hierdie soute voorspelis ontwikkel. Hierdie resultate kan gebruik word om die vorming van „ring-stacking‟ en „ring-laddering‟ in primêre ammonium karbosilaat soute te voorspel. Die resultate van die CSD ondersoek word bespreek in Hoofstuk 3. ‟n Eksperimentele studie is uitgevoer en die resultate hiervan komplimenteer die resultate van die CSD ondersoek. In die eksperimentele studie is 19 nuwe ammonium karboksilaat soute gekristaliseer, waarvan 2 hidraat-soute en 2 ko-kristal-van-soute is. Die eksperimentele resultate bevestig die bevindings van die CSD ondersoek, en dit word bespreek in Hoofstuk 4. Hierdie studie het gevind dat die beginsel van „ring-stacking‟ en „ring-laddering‟ kan in „n algemene vorm in die kristal strukture van organiese ammonium karboksilaat soute toegepas word. Die grootte van die katioon en anion in hierdie soute het ‟n beduidende effek op die vorming van strukturele motiewe in die vaste toestand. Interaksie tussen die katioon en anioon substituente speel „n belangrike rol in die vorming van spesifieke motiewe in ammonium karbosilaat soute.
25
Engelbrecht, Alma Margaretha. "Modelling of mass transfer in packing materials with cellular automata." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1914.
Full text
26
Bindis, Michael P. "Students' misconceptions about intermolecular forces as investigated through paper chromatography experiments and the Molecular Attractions Concept Inventory." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1379167186.
Full text
27
Marcelli, Gianluca, and g. marcelli@imperial ac uk. "The role of three-body interactions on the equilibrium and non-equilibrium properties of fluids from molecular simulation." Swinburne University of Technology. Centre for Molecular Simulation, 2001. http://adt.lib.swin.edu.au./public/adt-VSWT20060112.082425.
Full textAbstract:
The aim of this work is to use molecular simulation to investigate the role of
three-body interatomic potentials in noble gas systems for two distinct
phenomena: phase equilibria and shear flow. In particular we studied the
vapour-liquid coexisting phase for pure systems (argon, krypton and xenon) and
for an argon-krypton mixture, utilizing the technique called Monte Carlo Gibbs
ensemble. We also studied the dependence of the shear viscosity, pressure and
energy with the strain rate in planar Couette flow, using a non-equilibrium
molecular simulation (NEMD) technique.
The results we present in this work demonstrate that three-body interactions
play an important role in the overall interatomic interactions of noble gases. This
is demonstrated by the good agreement between our simulation results and the
experimental data for both equilibrium and non-equilibrium systems.
The good results for vapour-liquid coexisting phases encourage performing
further computer simulations with realistic potentials. This may improve the
prediction of quantities like critical temperature and density, in particular of
substances for which these properties are difficult to obtain from experiment.
We have demonstrated that use of accurate two- and three-body potentials for
shearing liquid argon and xenon displays significant departure from the
expected strain rate dependencies of the pressure, energy and shear viscosity.
For the first time, the pressure is convincingly observed to vary linearly with an
apparent analytic y2 dependence, in contrast to the predicted y3/2 dependence
of mode -coupling theory. Our best extrapolation of the zero -shear viscosity for
argon gives excellent agreement (within 1%) with the known experimental data.
To the best of our knowledge, this the first time that such accuracy has been
achieved with NEMD simulations. This encourages performing simulations with
accurate potentials for transport properties.
28
Oliveira, Mark Anthony. "Determining the Relative Energies of Formation of Co-Crystals : An Investigation into the Strengths of Intermolecular Packing Forces." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508601.
Full text
29
Stevenson, Kip Patrick. "Anisotropic potential energy surfaces for atmospheric gas : unsaturated hydrocarbon molecule interactions from differential scattering experiments /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/11613.
Full text
30
Narth, Christophe. "Développement de champs de forces polarisables : vers la dynamique moléculaire SIBFA." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066739/document.
Full textAbstract:
Le but de cette thèse est une revisite du potentiel SIBFA. Ceci inclut un travail et une réflexion sur la méthodologie de cette approche avec une implémentation proposant une utilisation plus large. De plus, une nouvelle calibration de champ de forces raffiné est permise aujourd’hui. En effet, la décomposition d’énergie intermoléculaire SAPT donne accès à toutes les composantes avec rigueur. La reproduction des résultats ab-initio par un potentiel analytique laisse entrevoir des applications prometteuses. Au-delà du coup de calcul considérablement réduit par rapport aux méthodes de chimie quantique, son intégration dans un code de dynamique moléculaire ouvre les portes à de nombreuses études encore plus prometteuses hors de portée de la chimie quantique. Enfin l’optimisation de ce code, avec une parallélisation bien étudiée, en feront un outil majeur de la biochimie. Dans une première partie, nous introduirons les notions et principes essentiels à la dynamique moléculaire. Un premier chapitre exposera la mécanique classique utilisé dans les programmes les plus distribués et utilisés. Un second chapitre introduira les méthodes permettant un meilleur traitement des interactions non-covalentes essentielles dans les études de complexes ligand-récepteur. Une seconde partie abordera de manière plus concrète la stratégie d’implémentation de SIBFA dans Tinker. Celle-ci s’organisera autour de trois chapitres, traitant chaque composante énergétique intermoléculaire. L’objectif de cette thèse est de proposer un socle solide autour du traitement des interactions non covalentes dans le cadre des champs de forces polarisables de dernières générations et de présenter le modèle d’eau hybride AMOEBA/SIBFAThe purpose of this thesis is to revisit the potential of SIBFA (Sum of Interactions Between Fragments Ab initio computed) [...]
31
Ramraj, Anitha. "Computational modelling of intermolecular interactions in bio, organic and nano molecules." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/computational-modelling-of-intermolecular-interactions-in-bio-organic-and-nano-molecules(7a41f3cd-1847-4ccf-8853-5fd8be2a2c15).html.
Full textAbstract:
We have investigated the noncovalent interactions in carbohydrate-aromatic interactions which are pivotal to the recognition of carbohydrates in proteins. We have employed quantum mechanical methods to study carbohydrate-aromatic complexes. Due to the importance of dispersion contribution to the interaction energy, we mainly use density functional theory augmented with an empirical correction for the dispersion interactions (DFT-D). We have validated this method with a limited number of high level ab initio calculations. We have also analysed the vibrational and NMR chemical shift characteristics using the DFT-D method. We have mainly studied the complexes involving β-glucose with 3-methylindole and p-hydroxytoluene, which are analogues of tryptophan and tyrosine, respectively. We find that the contribution for interaction energy mainly comes from CH/π and OH/π interactions. We find that the interaction energy of complexes involving CH/π and OH/π interactions is reflected in the associated blue and red shifts of vibrational spectrum. We also find that the interactions involving 3-methylindole are somewhat greater than those for p-hydroxytoluene. The C-H blueshifts are also in parallel with the predicted NMR proton shift. We have also tested different density functionals including both standard density functionals and newly developed M0x functionals and MP2 method for studying carbohydrate-aromatic complexes. The DFT-D method and M06 functionals of the M0x family are found to perform better, while B3LYP and BLYP functionals perform poorly. We find that the inclusion of a dispersion term to BLYP is found to perform better. The dispersion energy dominates over the interaction energy of carbohydrate-aromatic complexes. From the DFT-D calculations, we found that the complexes would be unstable without the contribution from dispersive energy. We have also studied the importance of noncovalent interactions in functionalization of nanotubes by nucleic acid bases and aromatic amino acids by using semi-empirical methods with dispersion term such asPM3-D and PM3-D*. We find that the both semi-empirical schemes give reasonable interaction energies with respect to DFT-D interaction energies. We have also used PM3-D method to study the adsorption of organic pollutants on graphene sheet and on nanotubes. We found that the semi-empirical schemes, which are faster and cheaper, are suitable to study these larger molecules involving noncovalent interactions and can be used as an alternative to DFT-D method. We have also studied the importance of dispersion interaction and the effect of steric hindrance in aggregation of functionalized anthracenes and pentacenes. We have also employed molecular dynamics simulation methods to study the aggregation of anthracene molecules in toluene solution.
32
Augustus, Adebayo Samuel. "Attractive steric interactions." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391708.
Full text
33
Oinuma, Ryoji. "Fundamental study of evaporation model in micron pore." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1239.
Full textAbstract:
As the demand for high performance small electronic devices has increased, heat removal
from these devices for space use is approaching critical limits. A heat pipe is a promising
device to enhance the heat removal performance due to the phase change phenomena for
space thermal management system. Even though a heat pipe has a big potential to remove
the thermal energy from a high heat flux source, the heat removal performance of heat
pipes cannot be predicted well since the first principle of evaporation has not been
established. The purpose of this study is to establish a method to apply the evaporation
model based on the statistical rate theory for engineering application including
vapor-liquid-structure intermolecular effect. The evaporation model is applied to the heat
pipe performance analysis through a pressure balance and an energy balance in the loop
heat pipe.
34
Khajehpour, Mazdak. "Solvent effects upon the charge-transfer reaction of the ADMA molecule in the excited state /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3025621.
Full text
35
Naseem-Khan, Sehr. "Development of a polarizable ab initio force field : From separability of intermolecular interactions to condensed phase properties." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS564.
Full textAbstract:
Grâce aux récents progrès de l’informatique, il devient alors possible d’utiliser des champs de forces polarisables sophistiqués tel que SIBFA. En effet, le potentiel intermoléculaire SIBFA et ses gradients sont désormais implémentés dans le code Tinker-HP. La calibration initiale de SIBFA est basée sur la méthode RVS, une méthode de décomposition de l’énergie seulement accessible au niveau Hartree-Fock. Ainsi, les objectifs de ce travail sont double : i) choisir une nouvelle méthode référence de décomposition de l’énergie afin d’obtenir les paramètres de SIBFA au niveau corrélé ; ii) réaliser des simulations de dynamiques moléculaires. La première partie de cette thèse est dédiée à l’étude ab initio de la séparabilité de l’interaction intermoléculaire prédit par les méthodes de décomposition de l’énergie dites variationnelles et perturbationnelles. Nous avons fait des améliorations de l’énergie d’induction au sein de la méthode SAPT(DFT) et nous avons proposé une nouvelle définition du transfert de charge. La seconde partie de cette thèse est dédiée au développement du potentiel polarisable de l’eau de SIBFA, et à notre stratégie pour calculer les propriétés en phase condensée. L’étude ab initio de la séparabilité de l’énergie totale intermoléculaire SAPT(DFT) a mené à une séparabilité totale des contributions du potentiel SIBFA au niveau post Hatree-Fock. Cette thèse marque un réel progrès pour le potentiel SIBFA qui finalise son approche bottom-up : à partir de calculs ab initio en phase gaz vers des simulations de dynamiques moléculaires et des prédictions précises des propriétés en phase condenséeThanks to the recent progresses of computer sciences de-multiplying the available computational resources, the possibility of using sophisticated polarizable force fields such as SIBFA becomes a reality. Indeed, the SIBFA intermolecular potential and its gradients are now implemented in the Tinker-HP package. The original calibration of SIBFA was based on the RVS method, an energy decomposition analysis only available at the Hartree–Fock level of theory. Therefore, the goals of this work are double : i) choosing a new energy decomposition analysis reference scheme in order to upgrade the SIBFA parameters at the correlated level of theory ; ii) performing molecular dynamics. The first part of this thesis is dedicated to the study of the separability of the ab initio intermolecular interaction energy predicted by both variational and perturbational Energy Decomposition Analysis methods. We have made improvements for the induction energy term within the SAPT(DFT) method, and we have proposed a new charge transfer definition. The second part of this thesis is dedicated to the development of the SIBFA polarizable water model and to our definition of a strategy to compute condensed phase properties. The ab initio study of the separability of the total SAPT(DFT) intermolecular interaction energy has led the SIBFA potential to achieve both full separability of its components and high accuracy at the post Hartree-Fock level. This thesis marks a turning-point for the SIBFA potential, finalizing its global bottom-up strategy going from gas phase ab initio computations towards molecular dynamics simulations and accurate condensed phase properties predictions
36
Oguz, Cihan. "Control-oriented modeling of discrete configuration molecular scale processes applications in polymer synthesis and thin film growth /." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19867.
Full textAbstract:
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Gallivan, Martha A.; Committee Member: Hess, Dennis; Committee Member: Lee, Jay H.; Committee Member: Li, Mo; Committee Member: Ludovice, Pete.
37
Butcher, Matthew James. "Adsorption and manipulation of doped fullerenes on silicon surfaces." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325717.
Full text
38
Moore, Alexander Patrick. "Computational properties of uranium-zirconium." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50339.
Full textAbstract:
The metallic binary-alloy fuel Uranium-Zirconium is important for use in the new generation of advanced fast reactors. Uranium-Zirconium goes through a phase transition at higher temperatures to a (gamma) Body Centered Cubic (BCC) phase. The BCC high temperature phase is particularly important since it corresponds to the temperature range in which the fast reactors will operate. A semi-empirical Modified Embedded Atom Method (MEAM) potential is presented for Uranium-Zirconium. This is the first interatomic potential created for the U-Zr system. The bulk physical properties of the Uranium-Zirconium binary alloy were reproduced using Molecular Dynamics (MD) and Monte Carlo (MC) simulations with the MEAM potential. The simulation of bulk metallic alloy separation and ordering phenomena on the atomic scale using iterative MD and MC simulations with interatomic potentials has never been done before. These simulations will help the fundamental understanding of complex phenomena in the metallic fuels. This is a large step in making a computationally acceptable fuel performance code, able to replicate and predict fuel behavior.
39
Pathak, Saurabh. "A Dynamic Model of the Magnetic Head Slider with Contact and Off-Track Motion Due to a Thermally Actuated Protrusion or a Moving Bump Involving Intermolecular Forces." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468408012.
Full text
40
Loots, Leigh-Anne. "Investigation of the co-crystallisation of N-heterocycles." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/4052.
Full textAbstract:
Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009.Co-crystals are excellent materials for studying intermolecular interactions in the solid-state and can be used to further our knowledge of the balance between strong and weak intermolecular interactions. The O–H∙∙∙∙∙∙Narom synthon was chosen as the focus of this investigation of hydrogen bonding motifs. The starting materials selected all have two hydrogen bond donor and/or acceptor sites for the formation of extended networks. All molecules are also aromatic such that the influence of weaker π∙∙∙∙∙∙π interactions can be included in the study. Two 3x3 grids of related co-crystals were produced from these starting materials and are reported in this thesis as part of an ongoing investigation into a broader set of co-crystals. A part of the work describes the investigation of co-crystals prepared by the combination of related benzenediol and diazine isomers taken from a 3x3 grid. The solid-state structures of each of the six starting materials are discussed briefly to describe the nature of intermolecular interactions involved in the single component crystals. Trends in hydrogen-bonding patterns as well as the weaker interactions identified in the starting materials, can be used to recognise those in the subsequent multi-component crystals. Thirteen co-crystal compounds were obtained, of which twelve structures are novel. Each of these co-crystal structures is discussed in terms of intermolecular interactions and packing in the solid state. Hydrogen-bonding patterns and structural similarities are highlighted in related co-crystal structures as well as between co-crystals and their respective starting materials. The combination of benzenediol isomers with benzodiazine isomers yielded seven novel co-crystal structures in a second 33 grid is reported. The structure of phthalazine, which has not yet been reported, is included in addition to these co-crystals, while the structures of quinazoline and quinoxaline that were retrieved from the CSD are discussed briefly. Co-crystal structures are discussed individually, focusing on the intermolecular interactions that are significant to the structural architecture of the compound. Certain co-crystals that display structural similarities with structures of the 3x3 grid, as well as with co-crystals presented in Chapter 3, are discussed in the relevant sections. Lastly, two extended pyridyl diyne ligands that were synthesised for use in future co-crystallisation studies similar to those reported earlier are briefly highlighted. The crystal structures of the pure compounds and of a hydrate of one of the ligands were obtained and discussed briefly. To date only one of these structures has been reported in the literature.
41
Corrêa, Charlane Cimini. "Síntese, caracterização e estrutura cristalina de polímeros de coordenação envolvendo metais de transição (Mn+2, Co+2, Cu+2 e Zn+2), ligantes nitrogenados multidentados e policarboxilatos." Universidade Federal de Juiz de Fora (UFJF), 2011. https://repositorio.ufjf.br/jspui/handle/ufjf/4434.
Full textAbstract:
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-08T17:51:58Z
No. of bitstreams: 1
charlaneciminicorrea.pdf: 11668631 bytes, checksum: a7ab701003fdf688b49377e542ceb430 (MD5)Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T14:03:22Z (GMT) No. of bitstreams: 1 charlaneciminicorrea.pdf: 11668631 bytes, checksum: a7ab701003fdf688b49377e542ceb430 (MD5)
Made available in DSpace on 2017-05-17T14:03:22Z (GMT). No. of bitstreams: 1 charlaneciminicorrea.pdf: 11668631 bytes, checksum: a7ab701003fdf688b49377e542ceb430 (MD5) Previous issue date: 2011-03-04
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Este trabalho de tese de doutorado consistiu na síntese e caracterização de arranjos supramoleculares com os metais Mn2+, Co2+, Cu2+ e Zn2+ da primeira série de transição contendo ligantes nitrogenados 1,3-bis(4-piridil)propano (BPP), sulfeto de di(4-piridila) (DPS) e dissulfeto de di(4-piridila) (DPSS) e policarboxilatos 1,2,4,5-benzenotetracarboxilato (BT), p-sulfobenzoato (SF) e 1,3,5-benzenotricarboxilato (BTC). Foram obtidos vinte e seis compostos que foram caracterizados por técnicas analíticas e espectroscópicas, tais como, análise elementar (CHN), análise térmica (TG/DTA) e espectroscopia vibracional (infravermelho e Raman). Dentre esses, vinte e dois compostos foram obtidos na forma de monocristais e tiveram suas estruturas determinadas por difração de raios X de monocristal. A análise térmica mostrou que todos os compostos apresentam-se hidratados, com moléculas de água de coordenação e/ou de cristalização. A espectroscopia vibracional foi importante para inferir sobre os modos de coordenação dos grupos carboxilatos através do cálculo do ∆ν (νassimCOO-νsimCOO). Nos compostos contendo o ligante BT, o grupo carboxilato atuou sempre de modo monodentado. Para os compostos com o ligante SF foram observados os modos monodentado e quelato e para o ligante BTC os modos monodentado, quelato e em ponte syn-syn e syn-anti. Foram descritas a síntese e caracterização dos compostos envolvendo o carboxilato BT e os ligantes nitrogenados BPP, DPS e DPSS que originaram onze complexos inéditos nomeados como: MnBTBPP, CoBTBPP, CuBTBPP, ZnBTBPP, MnBTDPS, CoBTDPS, CuBTDPS, ZnBTDPS, MnBTDPSS, CoBTDPSS e ZnBTDPSS. O ligante BT está presente em todos estes compostos e, com exceção do CoBTDPSS, apresentaram o ligante nitrogenado coordenado em ponte. Todos os compostos exceto o ZnBTBPP tiveram suas estruturas determinadas por difração de raios X de monocristal. Em especial, MnBTDPS e CoBTDPS são isoestruturais e os compostos ZnBTDPS e ZnBTDPSS apresentam estruturas semelhantes inclusive com a mesma topologia de rede. Realizou-se o estudo da síntese e caracterização de nove compostos utilizando o carboxilato SF e os ligantes nitrogenados BPP, DPS e DPSS nomeados, MnSFBPP, CoSFBPP, CuSFBPP, ZnSFBPP, CoSFDPS, CuSFDPS, ZnSFDPS, CoSFDPSS e ZnSFDPSS. Todos os compostos com exceção do CoSFDPSS tiveram suas estruturas determinadas por difração de raios X de monocristal. Em todas as estruturas analisadas os ligantes nitrogenados se coordenaram aos centros metálicos em ponte. No composto MnSFBPP o ligante SF não estava presente. Nos compostos CoSFBPP e CoSFDPS este ligante permaneceu na rede agindo como ânion estabilizando estas estruturas. Os arranjos bidimensional e tridimensional dos compostos foram observados pela presença de ligações de hidrogênio clássicas e não-clássicas, mostrando a importância das interações não covalentes na formação do arranjo supramolecular, bem como da estabilização das estruturas. Por fim, através das sínteses envolvendo o carboxilato BTC com os ligantes nitrogenados BPP, DPS e DPSS, seis complexos foram descritos como MnBTCBPP, CoBTCBPP, ZnBTCBPP, MnBTCDPS, ZnBTCDPS e ZnBTCDPSS. Os complexos CoBTCBPP, MnBTCDPS e ZnBTCDPS não apresentaram o ligante nitrogenado na estrutura, sendo que em todos eles pôde-se observar a presença do ligante BTC. Os complexos MnBTCBPP, CoBTCBPP, ZnBTCBPP e ZnBTCDPSS foram obtidos na forma de monocristais e tiveram suas estruturas cristalinas determinadas por difração de raios X de monocristal. Confirmaram-se então diversos modos de coordenação do ligante BTC nestes complexos tais como monodentado, quelato e em ponte syn-syn e syn-anti.
This work presents the synthesis and characterization of supramolecular arrays with Mn2+, Co2+, Cu2+ and Zn2+ first row transition metal ions, polydentate nitrogen ligands 1,3-bis(4-pyridyl) propane (BPP); di(4-pyridyl)sulfide (DPS) and di(4-pyridyl)disulfide (DPSS) and polycarboxylates 1,2,4,5-benzenotetracarboxylate (BT), p-sulfobenzoate (SF) and 1,3,5-benzenotricarboxylate (BTC). Twenty six compounds were synthesized and characterized of elemental analysis (CHN), thermal analysis (TG/DTA) and vibrational spectroscopy (infrared and Raman). Among these, twenty two compounds were isolated as single crystals and had their structures determined by single crystal X-ray diffraction analysis. Thermal analysis showed that all compounds are hydrated with coordination and/or lattice water molecules. Vibrational spectroscopy was very important to inform about the carboxylate groups coordination mode through ∆ν (νasymCOO - νsymCOO) value. In compounds containing BT ligand, the carboxylate group always acted in monodentate mode. For compounds containing SF ligands, monodentate and bidentatechelate modes were observed and for BTC ligand, monodentate, bidentate-chelate and syn-syn and syn-anti bridging modes were noted. The synthesis and characterization of compounds involving the BT carboxylate ligand and BPP, DPS and DPSS nitrogen ligands gives rise to eleven complexes described as MnBTBPP, CoBTBPP, CuBTBPP, ZnBTBPP, MnBTDPS, CoBTDPS, CuBTDPS, ZnBTDPS, MnBTDPSS, CoBTDPSS and ZnBTDPSS. BT ligand is present in all compounds and, except CoBTDPSS, they showed the nitrogen ligand in bridging coordination mode. All compounds, except ZnBTBPP, had their structures determined by single crystal X-ray diffraction analysis. In particular, MnBTDPS and CoBTDPS are isostructural and ZnBTDPS and ZnBTDPSS present similar structures with the same network topology. Studies of the synthesis and characterization of nine compounds using SF carboxylate and BPP, DPS and DPSS nitrogen ligands were realized, appointed as MnSFBPP, CoSFBPP, CuSFBPP, ZnSFBPP, CoSFDPS, CuSFDPS, ZnSFDPS, CoSFDPSS and ZnSFDPSS. All compounds, except CoSFDPSS, had their structures determined by single crystal X-ray diffraction analysis. In all structures the nitrogenated ligands coordinate to the metal centers in the bridging mode. For MnSFBPP the absence of ligand SF was noted. In CoSFBPP and CoSFDPS, this ligand remained uncoordinated, acting as a counter anion stabilizing these structures. The two- and three-dimensional arrays of the compounds were observed by the presence of classic and non-classic hydrogen bondings showing the importance of non-covalent interactions in the supramolecular arrangement, as well as in the structure stabilization. Finally, through the syntheses involving the BTC carboxylate with nitrogenated ligands BPP, DPS and DPSS, six complexes are described as MnBTCBPP, CoBTCBPP, ZnBTCBPP, MnBTCDPS, ZnBTCDPS and ZnBTCDPSS. CoBTCBPP, MnBTCDPS and ZnBTCDPS do not present nitrogen ligands in their structures and in all of them the presence of BTC ligand is observed. MnBTCBPP, CoBTCBPP, ZnBTCBPP and ZnBTCDPSS were obtained as single crystals and had their crystal structures determined by X-ray diffraction analysis. Great diversity of BTC ligand coordination modes as monodentate, chelate and syn-syn, syn-anti bridging modes were confirmed.
42
Jeannin, Marc. "Reconnaissance moléculaire dans des solutions ioniques paramagnétiques par relaxation nucléaire." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10070.
Full textAbstract:
Nous etudions la structure locale de solutions d'electrolytes comportant des impuretes parama/gnetiques par des mesures des temps de relaxation nucleaire en rmn. Grace aux equations integrales de la theorie des liquides et au modele de debye-huckel d'ecrantage du potentiel coulombien, nous avons obtenu des potentiels de force moyenne, puis des fonctions de correlation de paire pour des ions attractifs en solution. Nous expliquons ainsi les taux de relaxation intermoleculaires d'origine dipolaire magnetique des protons des cations tetramethylphosphonium couples aux spins electroniques des anions radicalaires nitrosodisulfonate en solution dans l'eau lourde. Nous avons ensuite developpe un modele permettant d'evaluer l'amplitude de la forte interaction hyperfine scalaire du spin electronique avec les noyaux de phosphore dont nous etudions les deplacements des raies de resonance en fonction de la concentration en ions paramagnetiques. Nous avons pu interpreter remarquablement le rapport anormal des temps de relaxation longitudinale et transverse intermoleculaires voisin de 1. 5 des noyaux de phosphore du tetramethylphosphonium en presence de radicaux nitrosodisulfonate a diverses concentrations ioniques. Nous confirmons ainsi la validite de notre modele decrivant les proprietes dynamiques d'ions attractifs dilues dans l'eau. Pour les valeurs absolues des taux de relaxation des phosphores, nos calculs conduisent a des valeurs un peu trop faibles. Notons cependant que notre modele ne dispose d'aucun parametre ajustable. Il convient de tenir compte egalement des effets d'anisotropie dans les processus diffusionnels a courte distance dus a la forme non spherique des ions. L'importance de ces effets d'anisotropie vient d'etre prouve sur un systeme plus simple constitue par une solution de radicaux tempol dans l'eau. L'introduction d'un potentiel effectif electrostatique anisotrope de paire donne alors un tres bon accord avec l'experience
43
Jacobs, Matheus Rychescki. "Parametrização de campo de força derivado de cálculos mecânico-quânticos para o cristal líquido 4-Ciano-4’-Pentilbifenila." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/171692.
Full textAbstract:
Simulações de Dinâmica Molecular tornaram-se uma ferramenta indispensável no estudo de sistemas em fase condensada, incluindo sistemas líquido-Cristalinos, e na predição de propriedades dinâmicas. Cristais líquidos possuem um leque enorme de aplicações, mas o estudo teórico destes sistemas torna-se complicado devido ao seu tamanho, ao método utilizado para obtenção dos parâmetros do campo de força e, principalmente, à transferibilidade dos parâmetros para outro estado termodinâmico. Tendo isso em vista, este trabalho propõe uma metodologia para parametrizar campos de força derivados de cálculos mecânico-quânticos que possuam um grau de transferibilidade confiável. O sistema escolhido neste trabalho foi o 4’-Pentil- 4-Carbonitrila, também conhecido como 5CB, pois o mesmo já é utilizado em diversos aparelhos óptico-eletrônicos; a parametrização intramolecular foi feita com o programa JOYCE, e a intermolecular, com o programa PICKY. Os parâmetros intramoleculares obtidos mostraram uma boa descrição da geometria interna do sistema, contribuindo para a parametrização intermolecular, a qual obteve uma excelente descrição de propriedades termodinâmicas. Este trabalho corrobora para a hipótese de que campos de força derivados de cálculos mecânico- quânticos podem descrever diferentes fases termodinâmicas com um alto grau de confiabilidade.Simulations using Molecular dynamics have become a powerful tool in the study of systems in condensed phase, including liquid-crystalline systems, and in the prediction of dynamical properties. Liquid Crystals have many applications, but the theoretical study of these systems is more complex because of their size, the method that was used in the force field parametrization and, mainly, because in most of the cases parameters cannot be transferred to another thermodynamical state. With that in mind, this work propose a methodology to parametrize force fields derived from quantummechanical calculations and which can be transferred to other thermodynamical state without losing important information. The chosen system in this work was the 4-Cyano-4’-Pentylbiphenyl, also known as 5CB, which have been used in many optical-electronic device and the intramolecular parametrization was done with the JOYCE program and the program PICKY was used in the intermolecular parametrization. The intramolecular parameters obtained show a good description of the internal geometry, contributes to the intermolecular parametrization, with we obtained an accurate description of the thermodynamical and physical chemical properties. This work corroborate to the hypothesis that force field derived from quantum-mechanical calculations can describe different thermodynamical states without losing important information.
44
VIGOUROUX, CECILE. "Microdynamique des solutions : influence des espèces paramagnétiques sur la relaxation en RMN." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10068.
Full textAbstract:
Ce travail concerne l'etude de differents systemes modeles en solution, representant les interactions inter- ou intramoleculaires. L'agent de perturbation est une espece paramagnetique. Nous utilisons le tempol (radical nitroxyde neutre), l'anion nitrosodisulfonate (radical nitroxyde charge) ou des cations lanthanide trivalents. La methode consiste a mesurer des taux de relaxation spin-reseau et des coefficients de diffusion translationnelle par resonance magnetique nucleaire, puis a elaborer un modele theorique ou les valeurs calculees sont les plus proches possibles des valeurs experimentales. Les resultats obtenus montrent la particularite du chloroforme (formation d'agregats entre molecules de chloroforme et de solute). Nous montrons egalement que le fluor est difficilement utilisable comme sonde de distance intramoleculaire pour nos systemes (sucre doublement marque par un radical tempol et un noyau #1#9f). Nous avons pu mettre en evidence par la mesure experimentale la formation d'associations entre un ion cs#+ et une molecule de tempol par un modele simultane de dynamique translationnelle et rotationnelle. Les resultats sur les cations lanthanides trivalents en presence de cations tetramethylammonium montrent que les modeles de mouvements relatifs d'ions spheriques sont parfaitement adaptes a ces systemes. Nous obtenons une adequation moins bonne en remplacant un radical neutre (tempol) par un radical charge (anion nitrosodisulfonate) en presence d'un autre anion (methanesulfonate). Nous pouvons alors etudier les proprietes electroniques des cations lanthanides. Nous montrons experimentalement la substitution des molecules d'eau par l'anion nitrate complexant dans le cas du gd#3#+. Nous estimons les parametres de champ cristallin des cations lanthanides hydrates par des mesures de deplacements paramagnetiques.
45
Silva, Marcos André do Rego. "Utilização do pireno como uma sonda fluorescente na investigação de ligações intermoleculares em misturas binárias de solventes." Florianópolis, SC, 2002. http://repositorio.ufsc.br/xmlui/handle/123456789/83428.
Full textAbstract:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Fisícas e Matemáticas. Programa de Pós-Graduação em Química.Made available in DSpace on 2012-10-19T23:56:59Z (GMT). No. of bitstreams: 1 184453.pdf: 484780 bytes, checksum: a508e5559db8ad2e5dfcfad0635c95cf (MD5)
Estudo da fluorescência do pireno em misturas binárias compreendendo um solvente não prótico [acetonitrila, N,N-dimetilformamida (DMF), dimetilsulfóxido (DMSO) e tetraidrofurano (THF)] e um solvente prótico (água, metanol, etanol, iso-propanol e n-butanol). Investiga para cada mistura a variação nos valores I/III, a razão da intensidade entre a primeira e a terceira banda das estruturas finas vibrônicas do espectro de emissão, junto com a variação do componente mais polar. Desenvolvimento e aplicação de um modelo de solvatação preferencial aos dados experimentais. Utilização do modelo para interpretação do fenômeno de sinergia observado em algumas misturas. Substituição da água por óxido de deutério em misturas com DMF e DMSO, para a análise do efeito isotópico. Interpretação de todos os resultados em termos de interações soluto-solvente e solvente-solvente.
46
Lekkas, I. "An analysis of atomic manipulation, intermolecular resolution and the artefacts of dynamic force microscopy." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/45151/.
Full textAbstract:
In this thesis we go through a journey of atomic manipulation of Pb dimers on Si(100), then we examine the limitations of AFM in inter- molecular resolution and we take a closer look at a very promising technique named simultaneous STM/AFM which opens new horizons in the field but is part of an ongoing debate as it is still under development. NC-AFM imaging of adsorbed Pb dimers on Si(100) provided detailed information of the Pb configuration, which agrees with previous STM studies. The lateral force required to move a Pb dimer is related to the adsorption of the dimer on the surface, the associated potential energy land scape and in some cases the interaction of the Pb dimer with its neighbouring dimers. In the next part of this thesis, we examine the adsorption of a small organic molecule (NTCDI) on Si(111)-(7×7) and we report two energetically preferable geometries among others. In the last part of this thesis, we present an analysis of the crosstalk effect using an Omicron commercial qPlus sensor and a home built sensor with two system configurations and we compare them with a Createc commercial system. The results show that in order to avoid crosstalk the range of the STM operational pre-amplifier and the optimal elec- tronics wiring play a major role.
47
Kang, Myungshim. "Molecular dynamics simulations and theory of intermolecular interactions in solutions." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1282.
Full text
48
Zepeda, Salvador. "Intermolecular interactions : from the hydrogen bond to biological function : an atomic force microscopy study of antifreeze glycoproteins and ice /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
Full text
49
Rixman, Monica Anne 1977. "Investigating the molecular origins of biocompatibility : intermolecular interactions between human serum albumin and various chemically modified surfaces via high resolution force spectroscopy." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/30118.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, February 2004.Includes bibliographical references (p. 200-215).
The first step in two of the most troublesome biological responses to the implantation of blood-contacting biomaterials, i.e. thrombosis and inflammation, is the adhesion of blood plasma proteins to the biomaterial surface, which may then initiate platelet adhesion and activation, and thereby set in motion a cascade of adverse host responses. If devices could be developed that prevent that first step from occurring altogether, a new generation of "stealth" biomaterials would be born. Such was the motivation of this project, which sought to investigate the constituent intermolecular interaction forces governing protein adhesion to biomaterials, using the technique of high resolution force spectroscopy. The model protein chosen for our study was human serum albumin (HSA), the smallest and most abundant blood protein in the human body, and typically the first to adsorb to a blood-contacting, implanted device. In the first stage of our investigation, HSA was covalently grafted to a nanosized probe tip at the end of a soft, microfabricated cantilever force transducer. The intermolecular interaction potential, U(D), was recorded between the HSA-modified probe tip and four different model surfaces, including: 1) gold, 2) a hydrophobic, CH3-terminated alkanethiol self-assembling monolayer (SAM), 3) a hydrophilic, COO-terminated alkanethiol SAM, and 4) individual, covalently end-grafted molecules of poly(ethylene oxide), in aqueous sodium phosphate buffer solution (PBS, ionic strength IS = 0.01M, pH = 7.4). Both theoretical and numerical modeling were employed to evaluate the experimental results on each of the different surfaces, and to characterize the nature of the protein-bound probe tip. In the second part of this study,
(cont.) we aimed to elucidate the various constituent intermolecular interaction forces contributing to U(D) by strategically manipulating experimental conditions such that we were able to isolate, and in some cases quantify, the electrostatic, steric, and hydrophobic components. It was found theoretically that electrostatic and steric forces accounted for approximately 8% and 4% of the total intermolecular interaction force; experimentally, these forces are observed to be completely dominated by a repulsive force which increases in magnitude as the ionic strength of the solution is increased. It is believed that this additional force is imparted by the PEO, and may be due to a change in the conformation of the PEO coil, or the structure of the network of water molecules in the space between the PEO coil and the approaching probe tip. The hydrophobic component was experimentally quantified to be approximately 20% of the total intermolecular interaction force at D [approx.] 1 nm. In the third part of this investigation, we sought to study the interactions between HSA and a series of oligosaccharide-functionalized surfaces inspired by the glycocalyx, which coats all living cells and is naturally and necessarily hemocompatible. The results of this study were then compared to experiments conducted in parallel on poly- and oligo(ethylene oxide) modified surfaces. Our results suggest that higher oligosaccharides ...
by Monica Ann Rixman.
Ph.D.
50
Feneyrou, Patrick. "Étude des propriétés optiques, linéaires et non linéaires, de la molécule et du cristal de 4-diéthylamino-(bêta)-nitrostyrène." Université Joseph Fourier (Grenoble ; 1971-2015), 1998. http://www.theses.fr/1998GRE10224.
Full textAbstract:
Ce travail concerne la spectroscopie de la molecule et du cristal de 4-(n, n diethylamino)-beta-nitrostyrene (deanst). Dans un premiere partie, les proprietes de la molecule en solution et en phase vapeur sont etudiees. Un calcul de chimie quantique permet de quantifier le transfert de charge intramoleculaire dont la resonance est observee experimentalement. Ce calcul permet egalement d'obtenir des distributions de charges associees aux dipoles moleculaires. Le spectre d'absorption a deux photons du deanst en solution dans le tetrahydrofurane est mesure par la technique d'ellipsometrie kerr. Ce spectre est bien decrit par une theorie simplifiee prenant en compte l'elargissement inhomogene et les etats vibrationnels de la transition a transfert de charge. Dans une seconde partie, les interactions intermoleculaires sont calculees dans le cadre de la theorie de frenkel-davydov. Le modele du dipole etendu est generalise a l'aide des distributions de charges calculees precedemment. Ce modele ameliore la description de la molecule lorsque la distance entre proches voisins est du meme ordre de grandeur que les dimensions moleculaires. Les differentes hypothese du modele utilises sont discutees. Des spectres de reflectivite enregistres selon deux plans cristallographiques demontrent les effets du couplage intermoleculaire : un eclatement de davydov de 5400 cm##1 est mesure. Le spectre d'excitation de fluorescence pompee a deux photons permet d'obtenir les informations sur les etats excitoniques pairs. Dans la derniere partie, l'influence de la focalisation du faisceau et de l'epaisseur de l'echantillon sur l'absorption non lineaire est etudiee. Une longueur effective d'interaction non lineaire est introduite. Un modele simplifie permet d'obtenir une expression de cette longueur effective sur l'axe optique et pour une faible non linearite. Des resultats experimentaux mesures sur des cristaux de 2-amino-5-nitro-pyridinium-chlorure illustrent ce calcul qui est ensuite generalise, par la technique numerique de propagation de faisceaux (bpm) a de plus fortes non linearites. Enfin, des effets d'absorption d'ordre plus eleve ainsi que de refraction non lineaire sont discutes.