  In this work the systems composed of particles interacting with hard
potential are investigated. These systems feature certain modifications to the
crystal structure - selected particles are replaced with ones that differ
slightly in their diameters. Such modifications, which can be thought of as
"inclusions", concern particles located in cylindrical nanochannels, oriented
in [001] direction. In this study, for the first time, additional constrains
have been imposed on the particles forming the inclusions. Namely, the replaced
spheres have been randomly grouped into neighbouring pairs which were connected
to form simple, di-atomic molecules. The results have been compared with
previously investigated systems with similar inclusions but without the
connections, i.e. filled only by spheres. The comparison of elastic properties
between these systems is presented. It is shown that inclusions filled with
dimers have different impact on the values of elastic compliances. It has been
demonstrated that by introducing a small number of molecules made of spheres
whose diameters differ from the rest of the particles forming the crystal, one
is able to modify the hardness and shear resistance of the f.c.c. crystal
without changing the Poisson's ratio (with respect to the analogous system
without additional constrains imposed on the inclusion particles).
