Investigation of the electronic structure of ice by high resolution x-ray spectroscopy

Abstract

Using a new high resolution concave grating grazing incidence spectrometer, we have investigated the oxygen K emission spectra of ice deposits formed near 0 °C and at liquid nitrogen temperature. The spectra, which have not been recorded so far, were excited by the radiation from a high power rotating x-ray anode loaded with 6 kV and 2.5 A. The spectral resolution amounted to 0.25 eV. The spectrum of the crystallized high temperature deposits follows qualitatively the predictions of a band structure calculation carried out by Resca and Resta (Ref.1). The spectrum of amorphous ice, which has been derived from the low temperature ice spectrum, exhibits features strongly resembling the spectrum of free water molecules as well as structures which can be related to the spectrum of crystallized ice. This suggests that amorphous ice contains molecules which are more or less properly bound in the sense of hydrogen bonding as well as quasifree molecules, the hydrogen bonds of which are severely disturbed or broken.