Dynamic signature of molecular association in methanol
Autor: | John R. D. Copley, C. E. Bertrand, Jeffrey L. Self, Antonio Faraone |
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Rok vydání: | 2016 |
Předmět: |
010304 chemical physics
Hydrogen bond Dynamic structure factor Neutron diffraction Supramolecular chemistry General Physics and Astronomy 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences chemistry.chemical_compound Molecular dynamics Crystallography chemistry Chemical physics 0103 physical sciences Quasielastic neutron scattering Deuterated methanol Physics::Chemical Physics Physical and Theoretical Chemistry 0210 nano-technology Supercooling |
Zdroj: | The Journal of chemical physics. 145(1) |
ISSN: | 1089-7690 |
Popis: | Quasielastic neutron scattering measurements and molecular dynamics simulations were combined to investigate the collective dynamics of deuterated methanol, CD3OD. In the experimentally determined dynamic structure factor, a slow, non-Fickian mode was observed in addition to the standard density-fluctuation heat mode. The simulation results indicate that the slow dynamical process originates from the hydrogen bonding of methanol molecules. The qualitative behavior of this mode is similar to the previously observed α-relaxation in supercooled water [M. C. Bellissent-Funel et al., Phys. Rev. Lett. 85, 3644 (2000)] which also originates from the formation and dissolution of hydrogen-bonded associates (supramolecular clusters). In methanol, however, this mode is distinguishable well above the freezing transition. This finding indicates that an emergent slow mode is not unique to supercooled water, but may instead be a general feature of hydrogen-bonding liquids and associating molecular liquids. |
Databáze: | OpenAIRE |
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