  Ultra-precise lattice parameter measurements in single crystals are
achievable, in principle, by X-ray multiple diffraction (XMD) experiments. Tiny
sample misalignments have hindered the systematic usage of XMD in studies where
accuracy is an important issue. In this work, theoretical basement and methods
for correcting general misalignment errors are presented. As a practical
demonstration, the induced strain of buried InAs quantum dots grown on GaAs
(001) substrates is determined. Such a demonstration confirms the possibility
to investigate epitaxial nanostructures via the strain field that they generate
in the substrate crystalline lattice.
  This work was supported by the Brazilian founding agencies FAPESP (grant
numbers 02/10185-3 and 02/10387-5), CNPq (proc. number 301617/95-3 and
150144/03-2) and LNLS (under proposal number D12A-XRD1 2490/03).
