Low Temperature Physics: 29, 386 (2003); https://doi.org/10.1063/1.1542502 (8 pages)
Fizika Nizkikh Temperatur: Volume 29, Number 5 (May 2003), p. 519-529    ( to contents , go back )

Atomic dynamics and problem of stability of structure of rare gase solid free clusters

E.T. Verkhovtseva, I.A. Gospodarev, O.V. Gryshayev, S.I. Kovalenko, D.D. Solnyshkin, E.S. Syrkin, and S.B. Feodosyev

B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Science of Ukraine, 47 Lenin Ave., Kharkov, 61103, Ukraine
E-mail: feodosiev@ilt.kharkov.ua

Received January 22, 2003


The cluster size dependences of mean square amplitudes of atoms in free clusters of rare-gas solids were explored theoretically and experimentally. The free clusters were formed due to homogeneous nucleations in an adiabatically dilating supersound jet. The mean square amplitudes of atoms were measured by the electron diffraction technique. The theoretical calculations were carried out by the J-matrix method. A series of distinctive features of the atomic dynamics of microclusters wee observed, the features being essential for the character of creation of their crystal structure and the requirements of its stability to be defined. It is shown that for clusters consisting of less than N ~ 103 atoms, a decrease in the cluster size produces a much more faster increase in the mean square amplitudes compared to that occurred with increasing the specific contribution of the surface. Besides, it is found that the free cluster FCC-structure contains generally defects such as twins (HCP-phase nuclei). One of the reasons of the origin of such defects is instability (anomalously high vibration amplitudes) of atoms of the coordination spheres of so-cold "apex" type.

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