Experimental evidence of low-density liquid water upon rapid decompression

Chuanlong Lin; Jesse S Smith; Stanislav V Sinogeikin; Guoyin Shen

doi:10.1073/pnas.1716310115

Experimental evidence of low-density liquid water upon rapid decompression

Proc Natl Acad Sci U S A. 2018 Feb 27;115(9):2010-2015. doi: 10.1073/pnas.1716310115. Epub 2018 Feb 12.

Authors

Chuanlong Lin¹, Jesse S Smith¹, Stanislav V Sinogeikin¹, Guoyin Shen²

Affiliations

¹ High Pressure Collaborative Access Team, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL 60439.
² High Pressure Collaborative Access Team, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL 60439 gshen@ciw.edu.

Abstract

Water is an extraordinary liquid, having a number of anomalous properties which become strongly enhanced in the supercooled region. Due to rapid crystallization of supercooled water, there exists a region that has been experimentally inaccessible for studying deeply supercooled bulk water. Using a rapid decompression technique integrated with in situ X-ray diffraction, we show that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140-165 K. The LDN subsequently crystallizes into ice-I_c through a diffusion-controlled process. Together with the change in crystallization rate with temperature, the experimental evidence indicates that the LDN is a low-density liquid (LDL). The measured X-ray diffraction data show that the LDL is tetrahedrally coordinated with the tetrahedral network fully developed and clearly linked to low-density amorphous ices. On the other hand, there is a distinct difference in structure between the LDL and supercooled water or liquid water in terms of the tetrahedral order parameter.

Keywords: low-density amorphous ice; low-density liquid; rapid decompression; time-resolved X-ray diffraction.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.