Electronic Transport Properties and Equation of State of Selenium at Temperatures up to 1900 K and Pressures up to 1800 bars
Liquid selenium consists mainly of long chain like polymer molecules Sen with n, the average degree of polymerisation, as large as 105 near its melting point . This molecular structure with nearly complete bond satisfaction of the individual divalent Se atoms leads to an electronic structure with closed valence electron shells, which is responsible for the semiconducting properties of liquid selenium . The purpose of this work was to investigate the changes of the electronic transport properties of liquid selenium, if the average molecular size is reduced to some few atoms. This can be achieved in the liquid under equilibrium conditions simply by raising the temperature to high enough values. Therefore measurements of the density d and simultaneous measurements of the dc-electrical conductivity σ and the absolute thermoelectric power S of liquid selenium were performed at temperatures up to 1900 K. To avoid the vaporization of the selenium and to maintain liquid like densities even at the highest temperatures, high pressures up to 1800 bars had to be applied. The experimental details will be published elsewhere.
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