Abstract
A rigorous treatment of the constraints imposed by site and body
symmetry on the orientational distribution of librating molecules is
presented in terms of multipole expansions. Radial densities of the
site-symmetric dynamic multipole expansion are linear combinations of
the radial densities of the body-symmetric static multipole expansion of
the same multipole order. The transformation from static to dynamic
radial densities is transmitted by libration matrices, which can be
included as parameters in a structure factor model. The matrix elements
are connected to the rotational dynamics of the molecule. They are
expansion coefficients of the orientational distribution in a basis
obtained by site and body symmetrization of the real Wigner functions.
Both symmetrizations are reduced to selecting terms from a general basis
according to simple index rules. Independence of the kind of density
function and Fourier invariance make the formalism useful in combined
neutron and X-ray diffraction studies.
Original language | English |
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Pages (from-to) | 201 - 210 |
Number of pages | 10 |
Journal | Acta crystallographica Section A: Crystal Physics, Diffraction, Theoretical and General Crystallography |
Volume | 37 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1981 |
MoE publication type | Not Eligible |