h1

TY  - THES
AU  - Meinerzhagen, Yannick Alexander
TI  - Weiterentwicklung und Anwendung der mehrdimensionalen Rietveldverfeinerung
PB  - RWTH Aachen University
VL  - Dissertation
CY  - Aachen
M1  - RWTH-2024-09969
SP  - 1 Online-Ressource : Illustrationen
PY  - 2024
N1  - Veröffentlicht auf dem Publikationsserver der RWTH Aachen University
N1  - Dissertation, RWTH Aachen University, 2024
AB  - This thesis presents the development and application of multidimensional Rietveld refinement. The method extracts information from measurement data from time-of-flight neutron powder diffractometers to a greater extent than previously possible. The method promises great added value, especially for the POWTEX@FRMII instrument currently under development. When evaluating the measurement data, information can be used for refinement that was previously discarded during data reduction.For the creation of multidimensional data sets, the data reduction was published in the computer program Mantid under the algorithm PowderReduceP2D. The data sets created in Mantid were refined with a modified version of the computer program GSAS-II and further functionalities were added for the multidimensional case. The multidimensional Rietveld refinement was tested on different samples and extended to the POWGEN@SNS and SNAP@SNS instruments as part of these tests. The first data set examined consisted of measurement data of BaZn(NCN)2 and was recorded with a test setup of the POWTEX detector on the POWGEN@SNS instrument. With the data from a high-pressure measurement of PbNCN on the SNAP@SNS instrument, multiphase refinements could be carried out multidimensionally for the first time.An internal structural change was also observed. Measurements of CuNCN and Fe[C5H5N]2[N(CN)2]2 on the instrument POWGEN@SNS allowed the testing of rigid bodies, constraints and the description of microstresses.A comparison of all refinement results shows that the multidimensional method provides more precise results, for example for lattice parameters or atomic positions.It also emphasizes the differences between comparable bonds more strongly.
LB  - PUB:(DE-HGF)11
DO  - DOI:10.18154/RWTH-2024-09969
UR  - https://publications.rwth-aachen.de/record/995530
ER  -