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Exposure to intense fluxes of ionizing radiation on metal targets causes various physical phenomena, such as changing the interatomic interaction potentials. It is known that intensive radiation generates ionized atoms within the track of a fast charged particle as well as near the solid surface. The potentials of interactions between these atoms and surrounding particles change considerably.
It is known that intensive radiation generates ionized atoms within the track of a fast charged particle as well as near the solid surface. The potentials of interactions between these atoms and surrounding particles change considerably. The knowledge of corresponding potentials of interatomic interaction is necessary for studying the behavior of partially or entirely ionized substance.
Therefore, aluminum was taken as an example studying the interatomic potentials in metal containing ionized states. Calculations were based on the method of pseudopotentials using Heine-Abarenkov-Animalu model potentials with parameters which were determined from spectroscopic terms of free ions following the method of quantum defect.
Ionization leads to the strong decrease in the depth of the first minimum of the potential function corresponding to the distance area between the nearest neighbors for three- or four-charged ions. Moreover, for the pair of particles with four charges the first minimum disappears absolutely. Atoms fall to the repulsion branch of interaction potential. As a result, the crystal lattice changes to the state of nonequilibrium.
The equations state for metal were provided on the basis of the pseudopotential method when part of the ionic cores further ionized. The isotherms were obtained for different degrees of the atoms ionization on the example of aluminium.
On the basis of pseudopotential approach, the behavior of interatomic interaction potentials under conditions of electronic subsystem excitation has been analyzed. It was discovered that thermal smearing of Fermi surface does not cause any essential change of interatomic interaction forces. At the same time local growth of conduction electron concentration causes “softening” of crystalline lattice when configuration with smaller interatomic distance becomes the equilibrium one. The potentials of interatomic interaction have been calculated for this case.
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