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Persistent URL http://purl.org/net/epubs/work/65697
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Record Id 65697
Title The temperature dependent structure of liquid 1-propanol as studied by neutron diffraction and EPSR simulations
Abstract The structure of liquid 1-propanol is investigated as a function of temperature using neutron diffraction together with Empirical Potential Structure Refinement modelling. The combined diffraction and computer modelling analysis demonstrates that propanol molecules form hydrogen bonded clusters with a relatively wide size distribution, which broadens at lower temperatures. We find that the cluster size distribution is well described by a recently proposed statistical model for branched H-bonded networks [P. Sillrén, J. Bielecki, J. Mattsson, L. Börjesson, and A. Matic, J. Chem. Phys. 136, 094514 (2012)]10.1063/1.3690137. The average cluster size increases from ?3 to 7 molecules, whilst the standard deviation of the size distribution increases from 3.3 to 8.5 as the temperature is decreased from 293 to 155 K. The clusters are slightly branched, with a higher degree of branching towards lower temperatures. An analysis of the cluster gyration tensor (Rmn) reveals an average elongated ellipsoidal shape with axes having proportions 1:1.4:1.9. We find that the average radius of gyration has a cluster size dependence consistent with that of fractal clusters, Rg???n1/D, with a fractal dimension D ? 2.20, which is close to D = 2.00 expected for an ideal random walk or D = 2.11 expected for reaction limited aggregation. The characteristic angles between the H-bonded OH-groups that constitute the clusters show only a weak temperature dependence with O–H?O angles becoming more narrowly distributed around 180° at lower temperatures.
Organisation ISIS , ISIS-NIMROD , STFC
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Language English (EN)
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Journal Article J Chem Phys 138, no. 21 (2013): 214501. doi:10.1063/1.4807863 2013