Accurate structure-factor measurements using high-energy synchrotron radiation: a test on cuprite, Cu2O

Abstract

Using high-energy synchrotron radiation, structure factors were measured on the triple-axis diffractometer at the HASYLAB beamline BW5. A data set for cuprite, Cu₂O, was recorded, and the excellent data quality [internal consistencyR_int(F²) = 0.0055] allowed full multipole refinements using the programVALRAY. Extinction was still significant, but small. Using data measured at 75, 100, 125 and 150 keV photon energies, it was possible to determine and separate extinction prior to the refinements. After evaluation and comparison of extinction-affected and extinction-free data, significant differences in the electron densities were found.