Dynamical structure factor for liquid bismuth

Abstract

The scattering function $S(Q,E)$ for liquid bismuth at 305\ifmmode^\circ\else\textdegree\fi{}C has been determined by neutron inelastic scattering in the wave-vector transfer range $1.6lQl7.2$ ${\mathrm{\AA{}}}^{\ensuremath{-}1}$ and for energy transfers $E$ up to about 20 meV. The measured $S(Q,E)$ satisfies the zeroth- and the second-moment relations within some few percent. The shoulder in the static structure factor $S(Q)$ gives rise to clearly visible effects also in the dynamical-scattering function. The full width at half maximum of $S(Q,E)$ exhibits an oscillation at a $Q$ value corresponding to the position of the shoulder. This fact together with some particular features in the same $Q$ range regarding the experimentally obtained spectrum of the longitudinal current-current correlation function indicates that the nature of the molecular dynamics in liquid bismuth is different as compared with simple liquid metals.