Abstract |
Carbon based materials and nanostructures are an important part of scientific research.Carbon is ubiquitous in nature, from the living organisms, which are all based onorganic compounds, to the universe, where it is the fourth most abundant element. Itsatoms have the ability to form diverse bonds resulting in various allotropes which alsoplay a crucial role in materials science and engineering. Understanding and simulatingseveral different bonding environments is a challenge for theory and computation andconsiderable effort focused on developing reliable and transferrable interatomicpotentials for classical molecular dynamics (MD) simulations. This thesis pertains tothe application of classical MD using such empirical potentials to create materials andmolecules consisting of carbon and hydrogen, determine their basic structural anddynamical properties, and compare the results with other theoretical methods, such asdensity functional theory and tight-binding, as well as experiment. More specifically,structure, bond lengths and vibrational spectra for diamond, graphene and itsnanoribbons, methane, benzene and hydrocarbon chains were examined with MDsimulations using bond order interatomic potentials. The simulation packageLAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) was used forthe MD and in-house software was developed for the calculation of vibrational spectrafrom the results of MD simulations using Fast Fourier Transform. Systematiccomparison of results shows overall agreement between empirical potentials andexperiment, with very few exceptions, where more accurate first principles methodsshould be used. Moreover, vibrational spectra are analyzed in terms of temperature,normal modes, and localized excitations
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