The use of neutron inelastic scattering measurements to determine the nature of the solid-state transitions in globular compounds is proposed and exemplified. Patterns were taken of the high- and low-temperature phases of solid cyclohexane, 2-2-dimethylbutane, and 1-4-diazo-bicyclo-(2.2.2)-octane. The first two have broad inelastic scattering peaks in the low-temperature phase. In the high-temperature phase these peaks disappear and the elastic peak broadens markedly. These changes are attributed to "quasi-free- rotation" of the molecules. Inelastic peaks do not appear in 1-4-diazo-bicyclo-(2.2.2)-octane, and the elastic peak does not broaden appreciably in the high-temperature phase. Self-diffusion coefficients D 3=4.5×10-5 cm2/sec for cyclohexane and D3=8.6×10-5 cm2/sec for 2-2-dimethylbutane were determined from the patterns of the liquids at 300°K using the "small motions" approximation. These values are larger than those obtained from NMR measurements, presumably as a result of irreversible rotation of the molecules.
Documento: | Artículo |
Título: | Neutron inelastic scattering studies of globular compounds |
Autor: | Becka, L.N. |
Filiación: | Atomic Energy of Canada, Limited, Chalk River, Ont., Canada National Research Council, Canada Departmento de Química Inorgánica y Físico- Química, Facultad de Ciencias Exactas y Naturales, Perú 222, Buenos Aires, Argentina |
Año: | 1963 |
Volumen: | 38 |
Número: | 7 |
Página de inicio: | 1685 |
Página de fin: | 1688 |
DOI: | http://dx.doi.org/10.1063/1.1776941 |
Título revista: | The Journal of Chemical Physics |
ISSN: | 00219606 |
PDF: | https://bibliotecadigital.exactas.uba.ar/download/paper/paper_00219606_v38_n7_p1685_Becka.pdf |
Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v38_n7_p1685_Becka |