A mode-coupling theory analysis of the observed diffusion anomaly in aqueous polyatomic ions

Banerjee, Puja and Bagchi, Biman (2017) A mode-coupling theory analysis of the observed diffusion anomaly in aqueous polyatomic ions. In: JOURNAL OF CHEMICAL PHYSICS, 147 (12).

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Abstract

In contrast to simple monatomic alkali and halide ions, complex polyatomic ions such as nitrate, acetate, nitrite, and chlorate have not been studied in any great detail. Experiments have shown that diffusion of polyatomic ions exhibits many remarkable anomalies; notable among them is the fact that polyatomic ions with similar size show large difference in their diffusivity values. This fact has drawn relatively little interest in scientific discussions. We show here that a mode-coupling theory can provide a physically meaningful interpretation of the anomalous diffusivity of polyatomic ions in water, by including the contribution of rotational jumps on translational friction. The two systems discussed here, namely, aqueous nitrate ion and aqueous acetate ion, although have similar ionic radii, exhibit largely different diffusivity values due to the differences in the rate of their rotational jump motions. We have further verified the mode-coupling theory formalism by comparing it with experimental and simulation results that agree well with the theoretical prediction. Published by AIP Publishing.

Item Type:	Journal Article
Publication:	JOURNAL OF CHEMICAL PHYSICS
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	23 Dec 2017 09:21
Last Modified:	23 Dec 2017 09:21
URI:	http://eprints.iisc.ac.in/id/eprint/58480

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