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Potential Energy Minimization as the Driving Force for Order and Disorder in Organic LayersWagner, Christian 07 June 2010 (has links)
The topic of this work is the structural characterization and theoretical modeling of organic single and heterolayers. The growth of sub-monolayers and monolayers (ML) of the two polycyclic aromatic hydrocarbons quaterrylene (QT) and hexa-peri-hexabenzocoronene (HBC) on Ag(111) and Au(111) was investigated. A transition from a disordered, isotropic phase to an ordered phase with increasing coverage was found. The lattice of the ordered phase turned out to be coverage dependent. The intermolecular potential was modeled including Coulomb and van der Waals interaction by a force-field approach. The postulated repulsive character of the potential could be connected to the non-uniform intramolecular charge distribution and to a screening of the van der Waals forces. Furthermore, the influence of the variable lattice constant on the epitaxial growth of HBC was studied. The second part of this work deals with a ML of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on a ML of HBC. In dependency on the initial lattice constant of HBC, a total of three line-on-line (LOL) and point-on-line coincident phases of PTCDA (with respect to HBC) was found. Following an analysis of the general properties of LOL coincident systems via force-field calculations, a new method to predict the structure of such systems is introduced.:1 Introduction
2 Experimental Methods
2.1 Organic molecular beam epitaxy
2.2 Scanning tunneling microscopy (STM)
2.3 Low-energy electron diffraction (LEED)
2.4 Molecules and substrates: Basic properties and literature review
2.4.1 3,4,9,10-Perylenetetracarboxylic dianhydride
2.4.2 Hexa-peri-hexabenzocoronene
2.4.3 Quaterrylene
2.4.4 Metal substrates: Au(111) and Ag(111)
3 Theory and Modeling
3.1 Reciprocal space and LEED
3.1.1 Fourier transform and geometrical LEED theory
3.1.2 Kinematic and dynamic LEED theory
3.1.3 Further applications of the Fourier transform
3.2 Computational chemistry
3.2.1 Calculating molecular properties
3.2.2 The atomic force-field method
3.2.3 Potential energy calculations in extended systems
4 Epitaxy in terms of potential energy
5 Interaction of QT and HBC at Sub-ML and ML Coverage
5.1 Experimental results
5.2 Modeling technique
5.3 Results of the model calculation
5.4 Discussion of results
5.5 Conclusion
6 The Ordered Phases of HBC on Ag(111) and Au(111
6.1 Geometrical analysis of epitaxy
6.2 Energetic gain of epitaxial structures
6.3 Comparison to experiment
6.4 Influence of the Au(111) surface reconstruction
6.5 Conclusion
7 Organic Heterosystems of PTCDA and HBC on Au(111)
7.1 PTCDA on Au(111) revisited
7.2 LEED and STM on PTCDA/HBC/Au(111) samples
7.2.1 A “compact” HBC layer substrate
7.2.2 A “loosely packed” HBC layer substrate
7.2.3 Summary of LEED results
7.2.4 STM results
7.3 Epitaxial relations in the system PTCDA/HBC/Au(111)
7.3.1 Geometrical analysis of epitaxy
7.3.2 Energetic gain of epitaxial structures
7.3.3 Mutual alignment of lattices
7.4 Heterosystems of PTCDA and HBC with inverted stacking sequence
8 General Properties of POL and LOL Epitaxy
8.1 A new coordinate system
8.2 Specific properties of the substrate-adsorbate potential
8.3 The “natural order” of the lattice lines
8.4 Prediction of epitaxial growth - a “LOL predictor”
8.4.1 Method
8.4.2 Results
9 General Conclusions and Future Perspectives
9.1 Conclusion
9.2 Outlook
Appendix
A.1 Conductance in a STM: The 1D WKB model
A.2 Extraction of the DOS from STS measurements by means of the 1D WKB model
A.3 Practical application of the 1D WKB model
A.4 The normalized differential conductivity
A.5 A new normalization method / Thema dieser Arbeit ist die strukturelle Charakterisierung von organischen Einfach- und Heterolagen sowie deren theoretische Beschreibung und Modellierung. Es wurden Submonolagen und Monolagen (ML) der polyzyklischen Kohlenwasserstoffe Quaterrylen (QT) und Hexa-peri-hexabenzocoronen (HBC) auf Ag(111) und Au(111) Einkristallen untersucht und ein Übergang von einer ungeordneten, isotropen Phase zu einer geordneten Phase mit steigender Bedeckung beobachtet. Die geordnete Phase wies dabei bedeckungsabhängige Gitterkonstanten auf. Das intermolekulare Potential wurde unter Berücksichtigung von Coulomb und van der Waals Anteilen mittels Kraftfeldmethoden modelliert. Der postulierte repulsive Charakter des Potentials konnte auf die Ladungsverteilung im Molekül und eine Abschwächung des van der Waals Potentials zurückgeführt werden. Weiterhin wurde der Einfluss der variablen HBC Gitterkonstante auf die epitaktische Relation des Gitters zum Metallsubstrat untersucht. Der zweite Teil der Arbeit widmet sich der Untersuchung einer ML 3,4,9,10-Perylenetetracarboxylic dianhydrid (PTCDA) auf einer ML HBC. Dabei wurden, in Abhängigkeit von der HBC Gitterkonstante, insgesamt drei verschiedene Typen von line-on-line bzw. point-on-line Epitaxie nachgewiesen. Im Anschluss an eine Analyse der generellen Eigenschaften solcher epitaktischer Lagen mittels Kraftfeldrechnungen wird eine neue Methode zur Vorhersage der Struktur konkreter Systeme vorgestellt.:1 Introduction
2 Experimental Methods
2.1 Organic molecular beam epitaxy
2.2 Scanning tunneling microscopy (STM)
2.3 Low-energy electron diffraction (LEED)
2.4 Molecules and substrates: Basic properties and literature review
2.4.1 3,4,9,10-Perylenetetracarboxylic dianhydride
2.4.2 Hexa-peri-hexabenzocoronene
2.4.3 Quaterrylene
2.4.4 Metal substrates: Au(111) and Ag(111)
3 Theory and Modeling
3.1 Reciprocal space and LEED
3.1.1 Fourier transform and geometrical LEED theory
3.1.2 Kinematic and dynamic LEED theory
3.1.3 Further applications of the Fourier transform
3.2 Computational chemistry
3.2.1 Calculating molecular properties
3.2.2 The atomic force-field method
3.2.3 Potential energy calculations in extended systems
4 Epitaxy in terms of potential energy
5 Interaction of QT and HBC at Sub-ML and ML Coverage
5.1 Experimental results
5.2 Modeling technique
5.3 Results of the model calculation
5.4 Discussion of results
5.5 Conclusion
6 The Ordered Phases of HBC on Ag(111) and Au(111
6.1 Geometrical analysis of epitaxy
6.2 Energetic gain of epitaxial structures
6.3 Comparison to experiment
6.4 Influence of the Au(111) surface reconstruction
6.5 Conclusion
7 Organic Heterosystems of PTCDA and HBC on Au(111)
7.1 PTCDA on Au(111) revisited
7.2 LEED and STM on PTCDA/HBC/Au(111) samples
7.2.1 A “compact” HBC layer substrate
7.2.2 A “loosely packed” HBC layer substrate
7.2.3 Summary of LEED results
7.2.4 STM results
7.3 Epitaxial relations in the system PTCDA/HBC/Au(111)
7.3.1 Geometrical analysis of epitaxy
7.3.2 Energetic gain of epitaxial structures
7.3.3 Mutual alignment of lattices
7.4 Heterosystems of PTCDA and HBC with inverted stacking sequence
8 General Properties of POL and LOL Epitaxy
8.1 A new coordinate system
8.2 Specific properties of the substrate-adsorbate potential
8.3 The “natural order” of the lattice lines
8.4 Prediction of epitaxial growth - a “LOL predictor”
8.4.1 Method
8.4.2 Results
9 General Conclusions and Future Perspectives
9.1 Conclusion
9.2 Outlook
Appendix
A.1 Conductance in a STM: The 1D WKB model
A.2 Extraction of the DOS from STS measurements by means of the 1D WKB model
A.3 Practical application of the 1D WKB model
A.4 The normalized differential conductivity
A.5 A new normalization method
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Bytový dům ve Zlíně / Residential building in ZlinJelínek, Roman January 2013 (has links)
The aim of this thesis is to elaborate project documentation for new construction of low-energy residential building with 16 luxury apartments, apartment without barriers and with pharmacy of basic type. It is a four-storey detached building without basement, with flat roof, roof terraces and with balconies. Residential building is located in one of the most enjoyable parts of the city of Zlín – Jižní Svahy II in the vicinity of Central park with bicycle path and with beautiful view of the Zlín. The building will be located on land plot No. 2144/46, where is still situated unfinished building "Torso" from the late 80 years. The residential building is designed in brick system Heluz, ceiling construction is made up of prestressed hollow core slabs, perimeter walls are with external thermal insulation composite system and external doors and windows are made of plastic and aluminum with triple glazing. For heating and water heating will be utilized renewables energy, such as heat pump and solar collectors. Residential units with three residential rooms are designed with a forced ventilation by means of ventilation units with heat recovery. The building also uses modern shielding elements such as outdoor blinds and horizontal sun breakers. The part of the project are also disposition studies, seminar work and energy part.
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