![]() Many configurations should be collected to ensure a local false minimum has not be arrived at, as could be the case if the weighting of the data is not suitable. If RMCProfile is run again from scratch or for a length of time at equilibrium, then a different snapshot will be produced, where the atoms will have moved but within the constraints of the data being fitted. If the fit is consistent with all the data available then the configuration will have the characteristic of the sample being studied, and can be considered to be a snapshot in time of the atom positions. This is not surprising when you consider we are using a model with ~104 atoms to describe a sample that contains of the order 1023 atoms. In this way the atomic configuration that RMCProfile produces will be consistent with the long and short range order information contained in the data and be a true holistic representation of the structure.Īs with any RMC method the configuration of atoms produced is not unique. the structure factor F(Q), the radial distribution function G(r) and the Bragg profile all at the same time. To this end you should aim to use RMCProfile to fit all aspects of the data simultaneously, i.e. ![]() In addition to a new program there is also a new methodology, which aims to supply the RMC algorithm with as much information as possible to ensure a physically sensible model. The main features are: fitting the Bragg profile directly the incorporation of data based polyhedral constraints swap moves for studying systems with site disordered - such as cation disorder or vacancies and now magnetic structures can also be modelled. ![]() RMCProfile is an extension of RMCA specifically for the study of disordered crystalline materials, although some of the new features may also be useful for studying amorphous materials. ![]()
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