ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
Following the discovery of a first-order phase transition in annealed KOH-doped ice at 72 K, which was identified as the order–disorder transition associated with the proton positions, a structural study has now been made. Powder neutron diffraction measurements on KOD-doped D2O above and below the phase transition, together with x-ray diffraction measurements, reveal a partial ordering of the hydrogen atoms at low temperatures. The equilibrium structure of ice at low tempertures has orthorhombic symmetry, space group Cmc21, with the same lattice as the high-temperature Ih (P63/mmc) modification. The structure is polar and there is evidence that the ordered domains are less than about 40 A(ring) in dimension.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.448763
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