Pressure-induced amorphization and existence of molecular and polymeric amorphous forms in dense SO <sub>2</sub>
Huichao Zhang, Ondrej Tóth, Xiaodi Liu, Roberto Bini, Eugene Gregoryanz, Philip Dalladay‐Simpson, Simone De Panfilis, Mario Santoro, Federico A. Gorelli, Roman Martoňák
Abstract
: molecular amorphous and polymeric amorphous, with the transition found at 26 GPa over a broad temperature regime, 77 K to 300 K. The transformation was observed by both Raman spectroscopy and X-ray diffraction in a diamond anvil cell. The results were corroborated by ab initio molecular dynamics simulations, where both forward and reverse transitions were detected, opening a window to detailed analysis of the respective local structures. The high-pressure polymeric amorphous form was found to consist mainly of disordered polymeric chains made of three-coordinated sulfur atoms connected via oxygen atoms, with few residual intact molecules. This study provides an example of polyamorphism in a system consisting of simple molecules with multiple bonds.