COHERENT EFFECTS AND RELAXATION PROCESSES IN LIQUID POTASSIUM

The coherent dynamic structure factor of liquid potassium has been obt ained from inelastic neutron scattering data al temperatures of 340, 4 40 and 550 K. The parts of dispersion curves for collective excitation s have been plotted and some of their characteristics have been analys ed. Represented in relative units, our experimental points are in an a greement with the ones for liquid rubidium and cesium. The molecular m emory effects are described within a framework of theoretical represen tations of a spatial dispersion for the relaxation parameter of non-Ma rkovian process. It has been found that molecular memory effects are i mportant for relaxation processes which are represented in inelastic b oth coherent and incoherent neutron scattering.