Iodine molecule modifications with high pressure

2020/04/16 by Jingming Shi, Shi, Jingming, Emiliano Fonda +24
Chemistry · Engineering · Medicine · Physics and Astronomy · #Chemical Physics (physics.chem-ph) #Chemical Thermodynamics and Molecular Structure #FOS: Physical sciences #Laser Design and Applications #Radiopharmaceutical Chemistry and Applications #physics.chem-ph

paper · pdf · doi:10.48550/arxiv.2004.07496

6 pages, 4 figures

openalex publication_date 2020/04/16 · arxiv created 2020/09/11 · arxiv updated 2020/09/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

Metallization and dissociation are key transformations in diatomic molecules at high densities particularly significant for modeling giant planets. Using X-ray absorption spectroscopy and atomistic modeling, we demonstrate that in halogens, the formation of a connected molecular structure takes place at pressures well below metallization. Here we show that the iodine diatomic molecule first elongates of ∼0.007 Å~up to a critical pressure of P_c \backsim7~GPa developing bonds between molecules. Then its length continuously decreases with pressure up to 15-20~GPa. Universal trends in halogens are shown and allow to predict for chlorine a pressure of 42±8~GPa for molecular bond-length reversal. Our findings tackle the molecule invariability paradigm in diatomic molecular phases at high pressures and may be generalized to other abundant diatomic molecules in the universe, including hydrogen.

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