Kryshtal' O. Changes in lattice parameter of island vacuum condensates

3. The experimental data on the size dependence of the lattice parameter in Cu, Ag, Au, Al and Ni island vacuum condensates prepared over a wide range of conditions have been obtained via thermal evaporation and magnetron sputtering technique. It has been established, that the lattice parameter of investigated metals prapared under conditions, when the influence of gas impurity is minimal, the lattice parameter of investigated elements decreases with the decrease of the characteristic size. The decrease of the lattice parameter has been explained in the framework of vacancy mechanism which is based on the account of increased concentration of vacancies in small particles as compared with this value for massive samples. The size dependence of formation energy of both volume and surface vacancies has been determined and it has been shown, that the decrease of the lattice parameter in small particles of fcc elements is caused by surface and near-surface vacancies. The expression for evaluation a vacancy volume has been obtained and the volume of a vacancy for a number of elements has been calculated. It has been shown, that the character of the size dependence of the lattice parameter (decrease or increase in comparison with massive samples) is determined by a ratio of the atom and vacancy volumes. The data on surface energy and it's size dependence in Cu, Ag, Au, Al and Ni small particles has been obtained.