Dielectric friction, violation of the Stokes-Einstein-Debye relation, and non-Gaussian transport dynamics of dipolar solutes in water

Tuhin Samanta; Dmitry V. Matyushov

doi:10.1103/physrevresearch.3.023025

Dielectric friction, violation of the Stokes-Einstein-Debye relation, and non-Gaussian transport dynamics of dipolar solutes in water

Physical Review Research ◽

10.1103/physrevresearch.3.023025 ◽

2021 ◽

Vol 3 (2) ◽

Author(s):

Tuhin Samanta ◽

Dmitry V. Matyushov

Keyword(s):

Dielectric Friction ◽

Transport Dynamics ◽

Non Gaussian

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NON-GAUSSIAN DISTRIBUTION IN RANDOM TRANSPORT DYNAMICS

International Journal of Modern Physics B ◽

10.1142/s0217979294001676 ◽

1994 ◽

Vol 08 (28) ◽

pp. 3887-3961 ◽

Cited By ~ 8

Author(s):

MISAKO TAKAYASU ◽

HIDEKI TAKAYASU ◽

Y-H. TAGUCHI

Keyword(s):

Steady State ◽

Diffusion Equation ◽

Mass Distribution ◽

Power Law ◽

Gaussian Distribution ◽

Discrete Space ◽

Transport Models ◽

Fluid Turbulence ◽

Transport Dynamics ◽

Non Gaussian

Statistical properties of random transport models defined on discrete space-time are investigated both numerically and analytically. As an extreme limit we first consider aggregation limit of massive particles. With the presence of permanent injection we have a nontrivial steady state where the mass distribution follows a power law. It is shown that the steady state is universal and very robust. Next, we analyze the cases of imperfect aggregation that a finite portion is transported at a time. We have a Gaussian fluctuation governed by the ordinary diffusion equation in the nonaggregation limit, while the system converges to the power law steady state in the aggregation limit even without injection. In the intermediate cases the fluctuations are always between Gaussian and the power law. Underlying relations to the exponential-like distributions in fluid turbulence are also discussed.

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Anharmonic Molecular Motion Drives Resonance Energy Transfer in peri-Arylene Dyads

Frontiers in Chemistry ◽

10.3389/fchem.2020.579166 ◽

2020 ◽

Vol 8 ◽

Author(s):

Vladislav Sláma ◽

Václav Perlík ◽

Heinz Langhals ◽

Andreas Walter ◽

Tomáš Mančal ◽

...

Keyword(s):

Quantum Chemical ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Unified Framework ◽

Time Resolved ◽

Transport Dynamics ◽

Donor And Acceptor ◽

Donor Acceptor ◽

Non Gaussian ◽

Good Agreement

Spectral and dynamical properties of molecular donor-acceptor systems strongly depend on the steric arrangement of the constituents with exciton coupling J as a key control parameter. In the present work we study two peri-arylene based dyads with orthogonal and parallel transition dipoles for donor and acceptor moieties, respectively. We show that the anharmonic multi-well character of the orthogonal dyad's intramolecular potential explains findings from both stationary and time-resolved absorption experiments. While for a parallel dyad, standard quantum chemical estimates of J at 0 K are in good agreement with experimental observations, J becomes vanishingly small for the orthogonal dyad, in contrast to its ultrafast experimental transfer times. This discrepancy is not resolved even by accounting for harmonic fluctuations along normal coordinates. We resolve this problem by supplementing quantum chemical approaches with dynamical sampling of fluctuating geometries. In contrast to the moderate Gaussian fluctuations of J for the parallel dyad, fluctuations for the orthogonal dyad are found to follow non-Gaussian statistics leading to significantly higher effective J in good agreement with experimental observations. In effort to apply a unified framework for treating the dynamics of optical coherence and excitonic populations of both dyads, we employ a vibronic approach treating electronic and selected vibrational degrees on an equal footing. This vibronic model is used to model absorption and fluorescence spectra as well as donor-acceptor transport dynamics and covers the more traditional categories of Förster and Redfield transport as limiting cases.

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