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21.—Riding Motion and Higher Cumulants in Crystallographic Models*

Published online by Cambridge University Press:  14 February 2012

G. S. Pawley
Affiliation:
Department of Physics, University of Edinburgh

Synopsis

The motion of hydrogen atoms due to the internal vibrational modes of a molecule is large and curvilinear. Because of the curvilinear motion the mean displacements of these atoms cannot be described by ellipsoids alone, but higher order terms or cumulants are necessary. Equations determining these terms from the usual riding motion are presented. By analysing a neutron diffraction study of high accuracy it is shown that the size of these higher cumulants is sufficient for them to be determinable. For deuterated samples however really high accuracy will be necessary in the diffraction experiment.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1972

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References

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