Time-resolved x-ray diffraction across water-ice-VI/VII transformations using the dynamic-DAC

[摘要] We present recent time-resolved x-ray diffraction data obtained across the solidification of water to ice-VI and -VII at different compression rates. The structural evolution of ice-VI to ice-VII, however, is not a sharp transition, but occurs rather coarsely. The diffraction data shows an anisotropic compression behavior for ice VI; that is, the c-axis is more compressible than the a-axis at the same compression rate. Nevertheless, the present equations of state of both ice-VI and ice-VII obtained under dynamic loadings agree well with those previously obtained under static conditions. Hence, the present study demonstrates that time-resolved x-ray diffraction coupled with the dynamic-DAC is an effective method for investigating details of the structural response of materials over a wide range of well-controlled compression rates. Finally, we found the evidence for an X-ray induced chemical reaction of water and ice-VI. The impurities, produced by the x-ray induced chemical reaction, inhibit the formation of amorphous ice.

[发布机构] CMMD, Physical and Life Science Direct., Lawrence Livermore National Laboratory, Livermore; CA; 94551, United States^1;Institute for Shock Physics, Department of Chemistry, Washington State University, Pullman; WA; 99164, United States^2;Photon Sciences, Deutsches-Elektronen Synchrotron DESY, Hamburg; D-22603, Germany^3

[关键词] Anisotropic compression;Compression rates;Dynamic loadings;Sharp transition;Static conditions;Structural evolution;Structural response;Time resolved x-ray diffractions