期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：27
DOI：10.1073/pnas.2117281119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
Understanding the phase behavior of H
2O is essential in geoscience, extreme biology, biological imaging, chemistry, and physics. Vitreous phases of H
2O are of particular importance since these phases avoid the typical expansion of H
2O during ice-crystal formation. Here, we confirm the existence of vitreous ice and ice VI in mixed-phase samples of H
2O at room temperature and high pressure. We show how Raman scattering and X-ray diffraction alone lead to misleading characterization and understanding of the mixed-phase material, a conclusion supported by molecular dynamics simulations. The coexistence of vitreous and crystalline components of H
2O under these conditions is crucial for experimental studies of biological systems. The results have implications for related metastable transitions in other materials under pressure.
Formation of vitreous ice during rapid compression of water at room temperature is important for biology and the study of biological systems. Here, we show that Raman spectra of rapidly compressed water at greater than 1 GPa at room temperature exhibits the signature of high-density amorphous ice, whereas the X-ray diffraction (XRD) pattern is dominated by crystalline ice VI. To resolve this apparent contradiction, we used molecular dynamics simulations to calculate full vibrational spectra and diffraction patterns of mixtures of vitreous ice and ice VI, including embedded interfaces between the two phases. We show quantitatively that Raman spectra, which probe the local polarizability with respect to atomic displacements, are dominated by the vitreous phase, whereas a small amount of the crystalline component is readily apparent by XRD. The results of our combined experimental and theoretical studies have implications for detecting vitreous phases of water, survival of biological systems under extreme conditions, and biological imaging. The results provide additional insight into the stable and metastable phases of H
2O as a function of pressure and temperature, as well as of other materials undergoing pressure-induced amorphization and other metastable transitions.
