[en] Theoretical or Mathematical/ bond angles ; bond lengths ; electrical conductivity transitions ; liquid structure ; melting ; Monte Carlo methods ; tellurium ; tight-binding calculations/ liquid Te ; atomic structure ; bonding mechanism ; tight-binding Monte Carlo simulation ; melting ; bond length ; short-long bond alternation ; bond angle ; electronic interaction ; lone pair orbitals ; semiconductor-metal transition ; 3.15 A ; Te/ A6125 Studies of specific liquid structures A6470D Solid-liquid transitions A7260 Mixed conductivity and conductivity transitions/ size 3.15E-10 m/ Te/el
[en] The atomic structure and bonding mechanism in liquid tellurium have been investigated by a tight-binding Monte Carlo simulation. On melting, the chain structure of the crystal is preserved in spite of some significant changes in the local atomic environment. A third covalent bond appears with a bond length (widely distributed around 3.15 Aring) intermediate between those characteristic of the crystal. A short-long alternation of the bonds takes place within the chains, in agreement with the most recent extended X-ray-absorption fine structure measurements. In addition, the bond angle within the chains is reduced. Our calculations clearly prove that these effects are due to the electronic interaction between the lone pair orbitals. The subsequent broadening of the lone pair band is responsible for the semiconductor to metal transition that takes place upon melting.