01809nas a2200193 4500008004100000022001400041245017000055210006900225260007100294300001600365490000800381520097700389100002201366700002101388700002001409700002201429700003401451856013001485 2015 eng d a1520-610600aDiffusion of small solute particles in viscous liquids: cage diffusion, a result of decoupling of solute-solvent dynamics, leads to amplification of solute diffusion0 aDiffusion of small solute particles in viscous liquids cage diff a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAUG a11169-111750 v1193 a

We study the diffusion of small solute particles through solvent by keeping the solute solvent interaction repulsive and varying the solvent properties. The study involves computer simulations, development of a new model to describe diffusion of small solutes in a solvent, and also mode coupling theory (MCT) calculations. In a viscous solvent, a small solute diffuses via coupling to the solvent hydrodynamic modes and also through the transient cages formed by the solvent. The model developed can estimate the independent contributions from these two different channels of diffusion. Although the solute diffusion in all the systems shows an amplification, the degree of it increases with solvent viscosity. The model correctly predicts that when the solvent viscosity is high, the solute primarily diffuses by exploiting the solvent cages. In such a scenario the MCT diffusion performed for a static solvent provides a correct estimation of the cage diffusion.

1 aAcharya, Sayantan1 aNandi, Manoj, K.1 aMandal, Arkajit1 aSarkar, Sucharita1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/diffusion-small-solute-particles-viscous-liquids-cage-diffusion-result-decoupling-solute-001641nas a2200169 4500008004100000022001400041245008500055210006900140260000900209300001100218490000800229520104300237100002201280700002501302700003401327856011001361 2017 eng d a0021-960600aFickian yet non-Gaussian behaviour: A dominant role of the intermittent dynamics0 aFickian yet nonGaussian behaviour A dominant role of the intermi cAPR  a1345040 v1463 a

We present a study of the dynamics of small solute particles in a solvent medium where the solute is much smaller in size, mimicking the diffusion of small particles in crowded environment. The solute exhibits Fickian diffusion arising from non-Gaussian Van Hove correlation function. Our study shows that there are at least two possible origins of this non-Gaussian behaviour: the decoupling of the solute-solvent dynamics and the intermittency in the solute motion, the latter playing a dominant role. In the former scenario when averaged over time long enough to explore different solvent environments, the dynamics recovers the Gaussian nature. In the case of intermittent dynamics the non-Gaussianity remains even after long averaging and the Gaussian behaviour is obtained at a much longer time. Our study further shows that only for an intermediate attractive solute-solvent interaction the dynamics of the solute is intermittent. The intermittency disappears for weaker or stronger attractions. Published by AIP Publishing.

1 aAcharya, Sayantan1 aNandi, Ujjwal, Kumar1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/fickian-yet-non-gaussian-behaviour-dominant-role-intermittent-dynamics01923nas a2200169 4500008004100000022001400041245010000055210006900155260000800224300001600232490000800248520129300256100002201549700002201571700003401593856012601627 2019 eng d a1520-610600aComparative study of anomalous size dependence of charged and neutral solute diffusion in water0 aComparative study of anomalous size dependence of charged and ne cDEC a10275-102850 v1233 a

We present a comparative study of size dependence of diffusion for charged and neutral solutes in water. Although both show nonmonotonicity of the size dependence of diffusion, their nature and origin are quite different. For neutral solutes, the peak position and the value of diffusion at the maximum are both independent of the solute water interaction. Interestingly, for charged solutes, with an increase in solute water interaction strength, the peak position shifts to lower solute sizes and with an increase in charge, it shifts to higher solute sizes. The diffusion value at the peak reduces with an increase in both solute water interaction and solute charge. We show that all these features observed for charged solutes can be understood in terms of the interplay between ionic and nonionic interactions which is definitely absent for neutral solutes. Some of the earlier studies addressing the nonmonotonicity in diffusion did suggest the interplay between the two interactions to be the cause. However, this is the first time we show that such an interplay gives rise to the nonmonotonicity in the potential energy which is a prerequisite for obtaining the nonmonotonicity in the diffusion. Such nonmonotonicity in the potential energy is absent for neutral solutes.

1 aAcharya, Sayantan1 aNandi, Ujjwal, K.1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/comparative-study-anomalous-size-dependence-charged-and-neutral-solute-diffusion-water00580nas a2200133 4500008004100000245010900041210006900150260000800219490000800227100002200235700002500257700003400282856013000316 2019 eng d00aFickian yet non-Gaussian behaviour: A dominant role of the intermittent dynamics (vol 146, 134504, 2017)0 aFickian yet nonGaussian behaviour A dominant role of the intermi cAUG0 v1511 aAcharya, Sayantan1 aNandi, Ujjwal, Kumar1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/fickian-yet-non-gaussian-behaviour-dominant-role-intermittent-dynamics-vol-146-134504-2017