We report new measurements of the densities of the coexisting liquid and vapour phases of the alkali metals K and Na. Comparison of the coexistence curve of K with those of Cs and Rb in reduced form shows that the alkali metals behave very similarly close to the critical temperatures. The experimental values of the critical constants T

Experimental results for fluid metals near the liquid-vapour critical point show that profound changes in the electronic structure of fluid metals occur in that region. A gradual transition from metallic to non-metallic behaviour occurs with decreasing density, which manifests itself in a corresponding strong thermodynamic state dependence of the interparticle interaction. The existence of this transition noticeably influences the thermodynamic features of the vapour-liquid phase transition of metals. Another equally important aspect of the problem is the size-dependent gradual evolution of metallic properties in isolated, microscopic metal clusters which clearly must be part of any detailed consideration of the liquid-vapour critical point phase transition of metals

Efficient multilayer electroluminescence devices with poly(m-phenylenevinylene-co-2,5-dioctyloxy-pphenylenevinylene) as the emissive layer A system of nanometer sized cobalt clusters surrounded by dielectric shells has been investigated by electrical dc conductivity measurements. The cobalt clusters have a diameter of 36 A and are surrounded by an approximately 12-A-thick layer of tetra-octyl-ammonium bromide surfactant molecules and poly(phenyl-p-phenylenevinylene). The conductivity in shows a temperature dependence ln(cr)m( To/T) 1'2 in the range IOOCTC240 K. At T>240 K, the temperature dependence of the conductivity demonstrates some peculiarities. Differential scanning analysis suggests that at 240

Experiments to generate a thin composite Fe-Ag film employing a sputter-gas-aggregation process are described. The magnetic properties are studied at low temperatures. In addition, the morphology is determined by high-resolution transmission electron microscopy and the structure by using x-ray diffraction and XAFS. Small clusters of about 11 Å in diameter are highly dispersed in an Ag matrix. They show the characteristics of interacting superparamagnets.

Fluid alkali metals are typical examples of materials whose electronic structures depend strongly on the thermodynamic state of the system. The most striking manifestation of this state dependence is the metal -nonmetal transition which occurs when the dense liquid evaporates to the dilute vapour or when the fluid is expanded by heating to its liquid -vapour critical point.The paper discusses equation of state data, electrical, and optical properties, and neutron scattering measurements of S( Q) and S( Q, w) with special emphasis on the change in these properties in the metal -nonmetal transition region. The shape of S( Q, w) changes considerably on approaching the transition from the high -density liquid side, indicating a change in the interparticle interaction and the molecular structure. S(Q, w) of rubidium in the density range between the melting point density and three times the critical density is characterized by the existence of well defined acoustic -phonon -like collective density excitations at high momentum transfer, whereas S(Q, w) at a density of about twice the critical density is consistent with excitations of an optic -type mode in which two species tend to move in opposite directions.[metal -nonmetal transition, supercritical fluid, alkali metal, static and dynamic structure, critical behaviour]