PROPERTIES OF ICE, PART II.

Modifications are reported of a previously described apparatus for the preparation of single crystals of pure and doped ice. Some results of using this apparatus to grow crystals of several crystallographic orientations are discussed. An effect of an electric field on the nucleation of ice at a metalwater interface is described. Various X-ray techniques for investigating the quality of ice crystals are discussed and experimental results of applying them to Alaskan Glacier crystals are given. Among the techniques used are the measurement of the half width of the reflection curve, the integrated reflecting power of a Laue reflection, studies with polarized X-rays and a transmission technique due to Lang. The thermal motion of ice molecules in a direction perpendicular to the c-axis and the temperature dependence of the lattice parameters of ice have been measured by X-ray techniques. Dielectric relaxation and electrical conductivity of ice are discussed. Experiments have been performed to determine the effect of length of the sample and to study the effect of small amounts of NH4F as a substitutional impurity. Special attention is given to long period dielectric processes. At least two such processes seem to be present, one which dominates the first 3 to 30 seconds of discharge and the other which determines the long time behavior. The possibility of altering the conductivity and dielectric relaxation of ice by optical generations of Bjerrum defects is explored and experiments to test this possibility are reported. Author