The dynamic structure factor S(Q,w) of liquid Bi was measured at 580K in the Q range from 0.15 to 0.6Å-1 using inelastic neutron scattering. The obtained spectra clearly demonstrate the existence of well defined longitudinal propagating modes. A positive dispersion is found in the low Q region, where the mode velocity undergoes a transition between the hydrodynamic value and a high frequency value 20% larger. The damping of the excitations does not follow the hydrodynamic Q2 trend and is stronger than in any metallic liquid investigated so far. The quasielastic lineshape contains a broad Q-independent Lorentzian contribution, other than a small sharp peak, which has yet been observed in liquid Hg and Ga.
High frequency dynamics of liquid bismuth
PETRILLO, Caterina;SACCHETTI, Francesco
2007
Abstract
The dynamic structure factor S(Q,w) of liquid Bi was measured at 580K in the Q range from 0.15 to 0.6Å-1 using inelastic neutron scattering. The obtained spectra clearly demonstrate the existence of well defined longitudinal propagating modes. A positive dispersion is found in the low Q region, where the mode velocity undergoes a transition between the hydrodynamic value and a high frequency value 20% larger. The damping of the excitations does not follow the hydrodynamic Q2 trend and is stronger than in any metallic liquid investigated so far. The quasielastic lineshape contains a broad Q-independent Lorentzian contribution, other than a small sharp peak, which has yet been observed in liquid Hg and Ga.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.