Neutron inelastic scattering studies of globular compounds

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. T...

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Publicado: 1963
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v38_n7_p1685_Becka
http://hdl.handle.net/20.500.12110/paper_00219606_v38_n7_p1685_Becka
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spelling paper:paper_00219606_v38_n7_p1685_Becka2023-06-08T14:44:33Z Neutron inelastic scattering studies of globular compounds 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. 1963 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v38_n7_p1685_Becka http://hdl.handle.net/20.500.12110/paper_00219606_v38_n7_p1685_Becka
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description 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.
title Neutron inelastic scattering studies of globular compounds
spellingShingle Neutron inelastic scattering studies of globular compounds
title_short Neutron inelastic scattering studies of globular compounds
title_full Neutron inelastic scattering studies of globular compounds
title_fullStr Neutron inelastic scattering studies of globular compounds
title_full_unstemmed Neutron inelastic scattering studies of globular compounds
title_sort neutron inelastic scattering studies of globular compounds
publishDate 1963
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v38_n7_p1685_Becka
http://hdl.handle.net/20.500.12110/paper_00219606_v38_n7_p1685_Becka
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