International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Debye’s temperature θ_D is the temperature border between areas, C_μ^V(Т) has constant value and, when T<θ_D, begins to decrease monotonically. θ_D is the crystal parameter, which allows to calculate the dimensional border between macro- and nanostates. The statement which is found in scientific discussions that θ_D depends on temperature is incorrect because it contradicts modern crystal-physical theories. The numerical value θ_D is defined experimentally and is related to the structure of crystals and to the processes taking place in them.

The structure of the bulk crystals allow to determine the habit of the nanocrystales on their base only as a source point. It is impossible to neglect the size, form and influence of surface. The liquids surface relatively quickly passes to equilibrium form when free energy is minimum. Debye’s temperature is rather arbitrary parameter. Its determination is based on some approach. However this parameter is introduced to the reference books and is broadly used in the crystal physics. Proposed strategy allows defining habit maximum size of nanoparticles on the base well known physics representations. The L–value is determined the bounder between sizes where it can be done value description and where it’s necessary to take into account the particle sizes.