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Title: Structural transformation between long and short-chain form of liquid sulfur from ab initio molecular dynamics

We present results of ab initio molecular dynamics study of the structural transformation occurring in hot liquid sulfur under high pressure, which corresponds to the recently observed chain-breakage phenomenon and to the electronic transition reported earlier. The transformation is temperature-induced and separates two distinct polymeric forms of liquid sulfur: high-temperature form composed of short chain-like fragments with open endings and low-temperature form with very long chains. We offer a structural description of the two liquid forms in terms of chain lengths, cross-linking, and chain geometry and investigate several physical properties. We conclude that the transformation is accompanied by changes in energy (but not density) as well as in diffusion coefficient and electronic properties—semiconductor-metal transition. We also describe the analogy of the investigated process to similar phenomena that take place in two other chalcogens selenium and tellurium. Finally, we remark that the behavior of heated liquid sulfur at ambient pressure might indicate a possible existence of a critical point in the low-pressure region of sulfur phase diagram.
Authors:
;  [1] ;  [2]
  1. Department of Experimental Physics, Comenius University, Mlynská Dolina F2, 842 48 Bratislava (Slovakia)
  2. Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava (Slovakia)
Publication Date:
OSTI Identifier:
22415678
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 15; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHALCOGENIDES; CROSS-LINKING; DENSITY; DIFFUSION; LIQUIDS; MOLECULAR DYNAMICS METHOD; PHASE DIAGRAMS; PRESSURE DEPENDENCE; SELENIUM; SEMICONDUCTOR MATERIALS; SULFUR; TELLURIUM