STRUCTURE OF LIQUID TELLURIUM - ENTANGLED, BROKEN CHAINS

The author presents a molecular-dynamics calculation of the structure of molten tellurium, based on effective interatomic forces derived from pseudopotential theory. Interatomic distances, coordination numbers, and bond angles are predicted in good agreement with recent neutron diffraction data. The analysis of the local topology shows that in liquid tellurium the atoms from a network of entangled broken chains with an average coordination number of N c=2.5 just above the melting point. The author shows that the physical mechanism stabilising this structure is the modulation of the random packing of the atoms in the melt by Friedel oscillations in the effective interatomic potential. He argues that this is just a generalised real-space description of the Peierls distortion argument conventionally used to explain the structure of crystalline Se and Te. The role of truly covalent interactions not included in this simple picture is discussed.