NEUTRON-SCATTERING STUDIES OF VAPOR-DEPOSITED AMORPHOUS ICE

Inelastic neutron scattering spectra were measured for amorphous ice H 2O and D2O produced by low-temperature and low-rate vapor deposition. The data show that the deposition produced the low-density amorphous f orm of ice, i.e., the high-density amorphous ice observed by x-ray [A. H. Narten, C. G. Venkatesh, and S. A. Rice, J. Chem. Phys. 64, 1106 ( 1976)] and electron diffraction [P. Jenniskens and D. F. Blake, Scienc e 265, 753 (1994)] under similar conditions was not detected. This res ult was confirmed by separate neutron diffraction experiments. Vibrati onal spectra of the deposited amorphous ice were dissimilar to that of ice I-h/I-C,, as was believed previously.