| Nanostructured materials are currently at the forefront of nearly every emerging industry, as they offer promising solutions to problems ranging from those facing energy technologies, to those concerning the structural integrity of materials. With all of these future applications, it is crucial that methods are developed which can offer accurate, and statistically reliable characterization of these materials in a reasonable amount of time. X-ray diffraction is one such method which is already widely available, and can offer further insight into the atomic structure, as well as, microstructure of nanomaterials.;This thesis work is then focused on investigating how different structural features of nanoparticles influence the line profiles of the x-ray powder diffraction pattern. Due to their extremely small size, the contribution from crystallite size broadening becomes the dominating feature in an observed diffraction peak. Therefore, the theory of size broadening was critically reviewed concerning the considerations necessary when the crystallite size approaches a few nanometers. Furthermore, the analysis of synthesized shape controlled platinum nanoparticles was carried out using a developed line profile analysis routine, based on the Debye function analysis (DFA) approach, to determine the distribution of particle size and shape in the sample.;The DFA method is based on the use of atomistic models to simulate the features in the powder diffraction pattern. The atomistic descriptions of molecular dynamics simulations was coupled with this approach, allowing for the further understanding of the pattern from nanoparticles. The techniques were developed to study how lattice dynamics, and the resulting thermal diffuse scattering, are affected by the small crystallite domains. Furthermore, the relaxation of structural models for nanoparticles by MD simulations allowed for the assessment of features which are a present in the powder pattern as a result of a strain gradient in the particle. In both cases the different results from Al and Cu particles were discussed. This study then improves the understanding diffraction from small crystallites, and showcases the level of insight which is achievable through the coupling of simulation and diffraction pattern analysis. |
