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arXiv · 2303.07870

Nature of Sub-diffusion Crossover in Molecular and Polymeric Glass-Formers

H. Srinivasan·V. K. Sharma·V. G. Sakai·S. Mitra
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Abstract

A crossover from a non-Gaussian to Gaussian sub-diffusion has been observed ubiquitously in various polymeric/molecular glass-formers. We have developed a framework which generalizes the fractional Brownian motion (fBm) model to incorporate non-Gaussian features by introducing a jump kernel. We illustrate that the non-Gaussian fBm (nGfBm) model accurately characterizes the sub-diffusion crossover. From the solutions of the nGfBm model, we gain insights into the nature of van-Hove self-correlation in non-Gaussian subdiffusive regime, which are found to exhibit exponential tails, providing first such experimental evidence in molecular and polymeric glass-formers. The results of the model are substantiated using incoherent quasielastic neutron scattering on glass-forming deep eutectic solvents.

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H. Srinivasan, V. K. Sharma, V. G. Sakai, S. Mitra. 2023-03-14. Nature of Sub-diffusion Crossover in Molecular and Polymeric Glass-Formers. https://arxiv.org/abs/2303.07870

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