THE SCATTERING OF SLOW NEUTRONS BY POLAR LIQUIDS (thesis)
A quasi-crystalline model of polar liquids for the analysis of slow- neutron scattering is proposed. Effects of the macroscopic medium are considered in terms of specific potentials that hinder molecular translations and rotations. By smearing the neighboring molecules over a spherical distribution and choosing a two-particle interaction that includes dipole-dipole forces, an effective potential for the center-of-mass degrees of freedom is derived. A sufficient condition for the parabolic approximation to this potential is estabiished. Hindrance in the rotational motion is treated by means of a coupling between the permanent electric dipole moment of the molecule and a local electric field that represents orientation-dependent effects of intermolecular forces. Under the condition of strong coupling, this hindering potential leads to useful wave functions for symmetric and linear molecules that describe free as well as hindered rotations. On the basis of the present treatment of molecular translations and rotations, the energy and angular differential scattering cross section is calculated without introducing further approximations. Particularly simple expressions are obtained when free-rotation energies are ignored. Energy distributions of neutrons scattered by hydrogen chloride and water are calculated. It is shown that hindered rotation effects are experimentally observable whereas the structure associated with hindered transiations can be observed only by means of high-resolution measurements. The present results provide a suitable basis for systematic studies of medium effects in polar liquids by inelastic slow- neutron scattering. Specific experiments are suggested. 67 references. (auth)
- Research Organization:
- Michigan. Univ., Ann Arbor. Michigan Memorial-Phoenix Project
- NSA Number:
- NSA-17-022539
- OSTI ID:
- 4713446
- Report Number(s):
- TID-18587
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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