Scientific Results

Pressure-induced amorphization and existence of molecular and polymeric amorphous forms in dense SO2

Year: 2020

Authors: Zhang H., Toth O., Liu XD., Bini R., Gregoryanz E., Dalladay-Simpson P., De Panfilis S., Santoro M., Gorelli FA., Martonak R.

Autors Affiliation: Chinese Acad Sci, Inst Solid State Phys, Key Lab Mat Phys, Hefei 230031, Peoples R China;‎ Univ Sci & Technol China, Hefei 230026, Peoples R China;‎ Comenius Univ, Fac Math Phys & Informat, Dept Expt Phys, Bratislava 84248, Slovakia; Univ Florence, Dept Chem, I-50121 Florence, Italy; European Lab Nonlinear Spect, I-50019 Sesto Fiorentino, Italy;‎ Univ Edinburgh, Sch Phys & Astron, Edinburgh EH9 3JZ, Midlothian, Scotland;‎ Univ Edinburgh, Ctr Sci Extreme Condit, Edinburgh EH9 3JZ, Midlothian, Scotland;‎ Ctr High Pressure Sci Technol Adv Res, Shanghai 201203, Peoples R China;‎ Ist Italiano Tecnol, Ctr Life Nano Sci, I-00161 Rome, Italy;]‎ CNR, INO, I-50125 Florence, Italy

Abstract: We report here the pressure-induced amorphization and reversible structural transformation between two amorphous forms of SO2: 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.

Journal/Review: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

Volume: 117 (16)      Pages from: 8736  to: 8742

KeyWords: polyamorphism; sulfur dioxide; high pressure; polymeric form
DOI: 10.1073/pnas.1917749117

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