High-pressure studies to determine the effects of volume and temperature on the lattice dynamics of molecular solids: N/sub 2/, CO/sub 2/, CH/sub 4/. Final report for period July 1, 1979-August 31, 1981
The main goal of the project was to carry out spectroscopic studies at different pressures and temperatures to provide additional information on the intermolecular potentials of simple molecular solids. A new high pressure infrared was specifically designed for the project. ir studies in ..cap alpha..-N/sub 2/ resulted in positive anharmonic self-energy shifts and a Grueneisen parameter of 3. Preliminary analysis of similar studies of solid methane indicate little anharmonicity in phase III and a transition to a phase IV which might explain a previously observed dielectric anomaly. Raman studies in solid CH/sub 4/ indicate an anisotropic intermolecular potential with a strong volume dependence, again little anharmonicity, and a III-IV phase transition which involves the reorientation of some molecules. In fluids, the density dependence on intramolecular frequencies has a striking resemblance to the intermolecular potential and molecular dynamics calculations of the effect are yet to be completed.
- Research Organization:
- Northeastern Univ., Boston, MA (USA)
- DOE Contract Number:
- AS02-79ER10443
- OSTI ID:
- 5800364
- Report Number(s):
- DOE/ER/10443-3; ON: DE82000398
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTROSCOPY
ALKANES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DENSITY
ELECTROMAGNETIC RADIATION
ELEMENTS
HIGH PRESSURE
HYDROCARBONS
INFRARED RADIATION
INFRARED SPECTROMETERS
INTERMOLECULAR FORCES
LATTICE PARAMETERS
LIGHT SCATTERING
MEASURING INSTRUMENTS
METHANE
MOLECULAR STRUCTURE
NITROGEN
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POTENTIALS
RADIATIONS
RAMAN EFFECT
SAMPLE PREPARATION
SCATTERING
SOLIDS
SPECTROMETERS
SPECTROSCOPY
TEMPERATURE DEPENDENCE