V. S. Stepanyuk

Microstructure and its relaxation in FeB amorphous system simulated by moleculular dynamics

A computer simulation by molecular dynamics for the system Fe85B15 is presented, to explore the dynamics of structural transformation from liquid to amorphous state by a rapid quench. The truncated Morse potential is used to simulate the atomic interactions. Possible models of the actual amorphous structures are suggested based on the statistical analysis of Voronoi polyhedra. The obtained metastable state depend on the methods of sample preparation.

Computer modeling of small clusters in nickel-phosphorus systems

Abstract The structures of a series of small clusters of Niue5f8P are calculated by molecular dynamics with two types of interacting potential: a Morse and empirical potential. A special effect of the P alloying into the small cluster of nickel is observed, namely the clusters consisting of two phosphorus are unstable. The explanation is given by the symmetries of the clusters.

The short-range order in amorphous NiP system changed by deep-freezing and subsequent relaxation

A model system of amorphous NiP is calculated by molecular dynamics. A rapid quench from liquid to solid and a subsequent deep-freezing to 5 K is investigated, simulating by computer the rapid cooling from 2000 K to 300 K, yielding a glass-state. Subsequently the system was further cooled, and then reheated to 300 K. A detailed Voronoi analysis is given to follow the change in short-range order. Characteristic differences have been observed between the two states at 300 K. A possible relaxation effect is discussed.

A “Giant Resonance” in Iron: Atom-Clusters-Crystal

Using the time-dependent local spin-density approximation and the model“atom in jellium” photoabsorpt ion cross-sections of iron clusters containing from 9 to 127 atoms have been calculated in the energy region of the giant resonance. The change of the shape of the giant resonance from a free Fe atom to iron clusters and bulk metal has been studied. It has been obtained that the intensity of the resonance is nonmonotonically decreased with the increase of iron atomic aggregation size.