Abstract
High-density amorphous ice (HDA), made by compression of hexagonal ice at 77 K, was heated at a constant pressure of 0.81 GPa up to 195 K and its phase transition followed by displacement-temperature curves. The crystalline phases recovered at 77 K and 1 bar were characterized by X-ray diffraction. Pure D2O ice IV and nearly pure H2O ice IV were formed on slow heating at a rate of ≈0.4 K min-1, whereas pure H2O and D2O ice XII were formed on fast heating at ≥15 K min-1. On heating HDA at rates inbetween, a mixture of ice IV and ice XII is obtained, where their relative yields depend in a systematic manner on the heating rate. Conversion of HDA into either ice IV or ice XII is an example of a “parallel reaction” where the relative yields of ice IV and ice XII can be controlled by temperature, that is in our approach by the rate of heating. It is conceivable that a similar behavior occurs on crystallization of the related pressure-amorphized silica.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.