Structure of a new dense amorphous ice.
The detailed structure of a new dense amorphous ice, VHDA, is determined by isotope substitution neutron diffraction. Its structure is characterized by a doubled occupancy of the stabilizing interstitial location that was found in high density amorphous ice, HDA. As would be expected for a thermally activated unlocking of the stabilizing "interstitial," the transition from VHDA to LDA (low-density amorphous ice) is very sharp. Although its higher density makes VHDA a better candidate than HDA for a physical manifestation of the second putative liquid phase of water, as for the HDA case, the VHDA to LDA transition also appears to be kinetically controlled.
Finney
J L
JL
Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
Bowron
D T
DT
Soper
A K
AK
Loerting
T
T
Mayer
E
E
Hallbrucker
A
A