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In situ Raman and optical microscopy of the relaxation behavior of amorphous ices under pressure
Author(s) -
Yoshimura Yukihiro,
Mao Hokwang,
Hemley Russell J.
Publication year - 2010
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2499
Subject(s) - amorphous solid , raman spectroscopy , metastability , relaxation (psychology) , crystallization , amorphous ice , in situ , optical microscope , chemistry , glass transition , microscopy , spectroscopy , analytical chemistry (journal) , crystallography , materials science , optics , physics , polymer , scanning electron microscope , chromatography , psychology , social psychology , organic chemistry , quantum mechanics , composite material
The transformation of low‐density amorphous (LDA) ice produced from high‐density amorphous (HDA) ice was studied up to 400 MPa as a function of temperature by in situ Raman spectroscopy and optical microscopy. Changes in these amorphous states of H 2 O were directly tracked without using emulsions to just above the crystallization temperature T x . The spectra show significant changes occurring above ∼125 K. The results are compared with data reported for the relaxation behavior of HDA, to form what we call relaxed HDA, or rHDA. We find a close connection with expanded HDA (eHDA), which is reported to exist as another metastable form in this P–T region. The observation of this temperature‐induced LDA transition under pressure complements the previously observed pressure‐induced reversible transition between LDA and HDA at 120–140 K. Copyright © 2009 John Wiley & Sons, Ltd.