Nanoscopic Length Scale Dependence of Hydrogen Bonded Molecular Associates' Dynamics in Methanol

Published

May 21, 2017

Author(s)

C. E. Bertrand, J. L. Self, John R. Copley, Antonio Faraone

Abstract

In a recent paper [C.E. Bertrand et al., J. Chem. Phys. 145, 014502 (2016)], we have shown that the collective dynamics of methanol shows a fast relaxation process related to the standard density-fluctuation heat mode and a slow non-Fickian mode originating from the hydrogen bonded molecular associates. Here we report on the lengthscale dependence of this slow relaxation process. Using Quasielastic Neutron Scattering (QENS) and Molecular Dynamics simulations we will show that the dynamics of the slow process is affected by the structuring of the associates, which is accessible through polarized neutron diffraction experiments. Using a series of partially deuterated samples, the dynamics of the associates is investigated and is found to have a similar timescale to the lifetime of hydrogen bonding in the system. Both the structural relaxation and the dynamics of the associates are thermally activated by the breaking of hydrogen bonding.

Citation

Journal of Chemical Physics

Volume

146

Issue

19

Pub Type

Journals

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Keywords

QENS

Citation

Bertrand, C. , Self, J. , Copley, J. and Faraone, A. (2017), Nanoscopic Length Scale Dependence of Hydrogen Bonded Molecular Associates' Dynamics in Methanol, Journal of Chemical Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921984 (Accessed October 26, 2025)