Charge density analysis from complementary high energy synchrotron X-ray and electron diffraction data

Differential convergent beam electron diffraction: Experiment and theory

“…5͒ is a marked improvement on previous QCBED from ␣-Al 2 O 3 with two-dimensional CBED data. 14,16,18,25,26 While it is true that centrosymmetrically averaged experimental intensity gradients come at the cost of a reduced signal-to-noise ratio ͑refer to Fig. 3͒ and the resulting magnitude of the signal is reduced by a factor of about 4 from the as-captured CBED data in the present case ͑see Fig.…”

“…This has been consistently observed in previous QCBED studies. 14,16,18,25,26 Residual strain is almost impossible to avoid in any CBED experiment and the effect of this is to distort the intensity distribution from the ideal symmetry resulting from a perfect crystal. In the present experiments, the integrity of each CBED pattern was checked by the examination of intensity profiles taken along loci that should possess centers of symmetry under ideal conditions.…”

“…Corundum has become established as a benchmark material for accurate experimental and theoretical charge-density studies 14,16,18,25,26,[34][35][36][37][38][39][40][41] and has been examined frequently by conventional 14,16,18,25 and TDQCBED. 26 Its high Debye temperature of 1045 K ͑Ref.…”

“…This approach is subsequently developed into a differential QCBED technique, which is tested against established methods with energyfiltered and unfiltered CBED patterns from ␣-Al 2 O 3 , a material for which structure factors have already been accurately measured. 14,16,18,25,26 …”

Refinement of crystal structural parameters and charge density using convergent-beam electron diffraction – the rhombohedral phase of LaCrO3

“…have been reported by many researchers (Vincent et al, 1984a,b;Zuo et al, 1989Zuo et al, , 1993Zuo et al, , 1997Zuo et al, , 1999Tanaka & Tsuda, 1990, 1991Deininger et al, 1994;Tsuda & Tanaka, 1995Saunders et al, 1995Saunders et al, , 1996Saunders et al, , 1999aHolmestad et al, 1995;Nu È chter et al, 1998a,b;Jansen et al, 1998;Wu et al, 1999;Streltsov et al, 2001). The method has the following advantages in contrast to the X-ray and neutron diffraction methods:…”