Scaling of the spin density

Coppens, P.; Su, Z.; Becker, P. J.

doi:10.1107/97809553602060000615

International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

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International Tables for Crystallography (2006). Vol. C. ch. 8.7, p. 730

Section 8.7.4.5.1.3. Scaling of the spin density

P. Coppens,^a Z. Su^b and P. J. Becker^c

^a 732 NSM Building, Department of Chemistry, State University of New York at Buffalo, Buffalo, NY 14260-3000, USA,^bDigital Equipment Co., 129 Parker Street, PKO1/C22, Maynard, MA 01754-2122, USA, and ^cEcole Centrale Paris, Centre de Recherche, Grand Voie des Vignes, F-92295 Châtenay Malabry CEDEX, France

8.7.4.5.1.3. Scaling of the spin density

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The magnetic structure factor is scaled to $[F_N({\bf h})]$ . Whether the nuclear structure factors are calculated from refined structural parameters or obtained directly from a measurement, their scale factor is not rigorously fixed.

As a result, it is not possible to obtain absolute values of the effective spins 〈S_n〉 from a magnetic neutron scattering experiment. It is necessary to scale them through the sum rule $[\textstyle\sum\limits _n\, \langle{\bf S}_n\rangle = {\boldmu}, \eqno (8.7.4.65)]$ where $[\boldmu]$ is the macroscopic magnetization of the sample.

The practical consequences of this constraint for a refinement are similar to the electroneutrality constraint in charge-density analysis (§8.7.3.3.1).

References

International Tables for Crystallography (2006). Vol. C. ch. 8.7, p. 730