All rights, especially that of tran5lation into foreign la&guagcs, reserved.I t is aho forbidden to reproduce this book, either whole or in part, by photo mechanical means (photostat, microfilm and/or microcard) or by other procedure without written permission from Springer-V erlag_

Single-crystal neutron-diffraction data have been used to refine the crystal structure of the paramagnetic cubic y phase of oxy'gen at 46'K. Tvm of the eight molecules in the Pgm3n unit cell are randomly oriented along the (111)axes at the 2(a) positions, and the remaining six along the (100) axes perpendicular to the fourfold inversion axes at the 6(d) positions. Associated with this disorder is a large librational motion with a rms amplitude of about 20 . Magnetic-form-factor values for 27 reflections have been measured by the polarized-neutron technique. Data were collected from large crystals subjected to an applied magnetic field of about 80 kOe in a specially designed split-coil superconducting magnet. The observed values are in good agreement with theoretical calculations described in the follovring paper based upon the usual molecular-orbital model with two unpaired electrons in the pg antibonding orbitals.

For the past 6 years pulsed neutron sources have been successfully used for studies of the kinetic behavior of neutrons in matter. Three main fields of interest have been particularly stressed: neutronlifetime measurementsinmoderators; reactivity measurements on reactor systems; and

No abstract

No abstract