SKM 2021 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 5: Topical Session Interface Dominated Phenomena - Poster
MM 5.9: Poster
Tuesday, September 28, 2021, 10:00–12:45, P
The methods of neutron diffraction intensity calculation — •Anastasiia Kuznetsova1, Jie Luo2, Hareesh Chavana3, Veronika Reich1, Sebastian Busch1, and Martin Müller4 — 1GEMS at MLZ, Hereon, Lichtenbergstr. 1, 85748 Garching b. München, Germany — 2ILL, 71 avenue des Martyrs, 38000 Grenoble, France — 3ICG Place Eugene Bataillon, Bat. 15, 34095 Montpellier, France — 4Hereon, Max-Planck-Str. 1, 21502 Geesthacht, Germany
Neutron diffraction intensity on a crystal is commonly calculated as crystal's structure factor squared. The SASSENA program, suitable for atomic movement modeling, and the Debye formula, applicable for any material, not obligatory a periodic one, were tested for calculation of diffraction on crystalline powders. Mono- and biatomic structures of cP, bcc, and fcc crystal lattices of two different sizes each were used as model crystals. Furthermore, for Po, which data on scattering length were not listed, it was set artificially and also varied. The first method sums up reflections from all crystalline planes for the same Q-vector; the second one takes into account both crystalline structure and atomic motions; the third one spherically averages all possible orientations of the system. The resulting curves were juxtaposed and for Debye formula, the intensities were also correlated with structure factors squared and plotted against Q to obtain some kind of dependence. Given their results' difference, one has to choose a proper calculation method and to justify their choice. Due to some Q-dependence of intensities ratios the presence of some explanation for the divergence among the results of both formulas was assumed.