  In this paper we show that 1-electron properties such as Compton profiles and
structure factors of crystals can be asymptotically retrieved through
cluster-based calculations, followed by an appropriate partition of the
1-electron reduced density matrix (1RDM). This approach, conceptually simple,
is checked with respects to both position and momentum spaces simultaneously
for insulators and a covalent crystal. Restricting the calculations to small
clusters further enables a fair description of local correlation effects in
ionic compounds, which improves both Compton profiles and structure factors vs.
their experimentally determined counterparts.
