Hartree–Fock atomic scattering factors for the iron transition series

Abstract

Atomic scattering factors for thirty-five atoms and ions of the iron group transition series (Se through Cu) have been determined from Watson's recently calculated Hartree-Fock wave functions and compared with the few other available calculations. Principal scattering factors were also computed, following the methods of Freeman, for the 3d electrons of those atoms containing nonspherical charge distributions. As shown by Weiss & Freeman these are all that are needed for determining (from the measured neutron form factor) the spatial symmetry of the outer electrons in magnetic materials. Argon core scattering factors were also calculated, and, on the basis of these new results, the question of the constancy of the argon core is discussed quantitatively. Analysis of the 3d transforms for different stages of ionization shows another difficulty for the Weiss-:DeMarco experiments.

A powder neutron diffraction investigation of the nuclear and magnetic structure of Sr2Fe2O5

“…The octahedral Fe 3+ results closely follow the free ion curve but the tetrahedral values show a marked contraction. In our powder experiment no information could be obtained concerning the shape of the form factor and the free ion data of Watson & Freeman (1961) have been used. A contraction of the Fe 3+ form factor would result in our value of the tetrahedral moment being too low by 2-3 %.…”

“…The complex nature of the powder pattern excluded the possibility of refinement based on integrated intensities and instead the structural parameters were refined by least-squares analysis of the diffraction profile (Rietveld, 1967) All the data collected in the range 8°<20<95 ° were used in the refinement and the contribution to the profile from the background was estimated by hand. The free ion Fe 3÷ form factor (Watson & Freeman, 1961) and the following scattering lengths were used: bo--0-58 × 10 -12 cm; bFe=0"951 × 10 -12 cm (Neutron Diffraction Commission, 1972) and bsr--0"692 × 10 -12 cm (Cooper & Rouse, 1972). …”

Bonding in a binuclear metal carbonyl: experimental charge density in Mn2(CO)10

“…The total number of valence electrons was assumed to be seven, as direct integration had shown that the charge of Mn was very small. The calculation was done for the two configurations 3d54s 2 (International Tables for X-ray Crystallography, 1974) and 3d 7 (Watson & Freeman, 1961). The proportionality coefficients, obtained by fitting the theoretical and experimental curves up to 0.6/k from the Mn nucleus, were 2.0 (2) and 2.3 (2) respectively.…”

1,2,4-Triazole Complexes XII * . Magnetic properties of Fe (1, 2, 4-triazole)2 (NCS)2, a quasi two-dimensional S = ½. antiferromagnet with hidden canting.

“…Atomic form factors for Fe(II) were taken from Watson and Freeman [22] and scattering lengths from Bacon [23]. The agreement indices which are referred to have been given previously [4,21].…”