Study of V3Si lattice dynamics

The paper deals with the investigation of dynamics of V3Si lattice vibrations. The low-lying dispersion curves of transverse acoustic and optical vibrations, propagating in the [110] and [100] directions, have been measured by the method of coherent inelastic scattering of thermal neutrons on a V3Si single crystal specimen. The measurements have been taken at a room temperature. The data for both acoustic branches are in agreement with results of previous papers. Theoretical calculation has been carried out in the framework of the developed two-band model. The model describes qualitatively the temperature softening of the acoustic phonon branch observed in the [110] direction, but overestimates the frequencies. It has been obtained by the Fourior series approximating that the branches in the [100] direction (along the vanadium atom chain) are well described by one of the terms of the series expansion. It indicates that in the [100] direction interaction with close neighbours is defining