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Study of interactions of organic matter and its components via molecular dynamics
BARVÍKOVÁ, Hana
Humic acids and humates are principal components of humic substances major organic constituents of soil, peat, coal and water around the world. I was involved in research into molecular dynamics simulations of interactions of quartz surfaces with aqueous solutions of ions and small organic molecules representing basic building blocks of larger biomolecules and functional groups of organic matter. We studied interactions of molecules with surfaces for a set of surface charge densities corresponding to the experimentally or environmentally relevant ranges of pH values employing molecular mechanics, molecular dynamics and ab initio techniques. Simulated quartz surfaces covered the range of surface charge densities 0.00, -0.03, -0.06 and -0.12 C-m-2, approximately corresponding to pH values 4.5, 7.5, 9.5 and 11. As model molecules, benzoic acid, phenol, o-salicylic acid and their conjugated bases were chosen. My task was to prepare topologies and parametric models of selected organic matter basic building blocks organic molecules. I focused on studying interactions of these molecules in an aqueous environment with mineral surface quartz. The aim was to process simulation results and analyse conformations of the adsorption complexes and their thermodynamic properties such as interaction energies, free energies and adsorption geometries.
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Computer simulation of interactions of molecules with mineral surfaces
BARVÍKOVÁ, Hana
This thesis is focused on molecular dynamics, modelling interactions and their simulation. One of the tasks was to familiarize with GROMACS, a molecular dynamics simulation software. This work also introduces the basics of molecular dynamics and modelling interactions of organic molecules with mineral surfaces. The aim of the thesis was to solve model tasks in GROMACS and analyze the output results. The thesis describes some of the most important file formats and utilities that are needed for working with GROMACS and the use of both the formats and the utilities. In this program, I built up several systems consisting of combinations of organic molecules such as benzoic acid, phenol, salicylic acid and their conjugate bases with mineral surfaces (quartz crystal) of different surface charge density. Furthermore I analyzed the results of these simulations, behaviour of the structures and adsorption geometries and interaction energies within these systems. The thesis might also serve as a quick introduction and familiarization with GROMACS with emphasis on simulations and analysis of systems with planar interfaces. Within the MetaCentrum Project I worked on the Hermes Computer Cluster belonging to the Faculty of Science at the University of South Bohemia.
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Software for molecular dynamics
ŠILHAVÁ, Kristýna
The software for molecular dynamics provides the ability of simulating systems that consist of millions of particles, just for a few nanoseconds. This method allows for the carrying out of virtual experiments without real laboratory equipment and only with computer technology. Molecular dynamics play an important role in understanding the structure and function of biological, organic and inorganic systems. The objective of this thesis was to introduce the basics of molecular dynamics, solve model tasks in Amber software and Gromacs and to compare their capabilities. I have worked on the Hermes Computer Cluster that belongs to the Faculty of Science at the University of South Bohemia and this was part of the MetaCentrum Project. I have worked with both programs using the command line of the Linux Operating System. This thesis describes all of the file formats that are needed for working with these programs, and how they are to be used. I have built up several systems in Gromacs and Amber: 1) water 2) water and ions 3) solvated lysozyme. Based upon these sample systems, I have compared the basic utilities for preparation, the execution and the analysis of these simulations. This thesis should serve as a quick introduction and familiarization with Amber software and Gromacs.
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