Collective dynamics in molten potassium: An inelastic x-ray scattering study

The high-frequency collective dynamics of molten potassium was disucssed using inelastic x-ray scattering. It was found that a two-step relaxation scenario similar to that found in other liquid metals applied to liquid potassium. It was found that the Brillouin linewidth was not related to the whole longitudinal velocity but rather to the 'microscopic' part of the viscosity. The microscopic relaxation process which were traced back to the presence of 'instantaneous' disorder rather than to the crossover from a liquid to solidlike response was also elaborated.