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

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Main Authors: Srinivasan, H., Sharma, V. K., Sakai, V. G., Mitra, S.
Format: Preprint
Published: 2023
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author Srinivasan, H.
Sharma, V. K.
Sakai, V. G.
Mitra, S.
author_facet Srinivasan, H.
Sharma, V. K.
Sakai, V. G.
Mitra, S.
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2303_07870
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Nature of Sub-diffusion Crossover in Molecular and Polymeric Glass-Formers
Srinivasan, H.
Sharma, V. K.
Sakai, V. G.
Mitra, S.
Soft Condensed Matter
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.
title Nature of Sub-diffusion Crossover in Molecular and Polymeric Glass-Formers
topic Soft Condensed Matter
url https://arxiv.org/abs/2303.07870