Effect of surface roughness on interfacial reaction–diffusion admittance

Kant, Rama; Rangarajan, S.K.

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/2728

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DC Field	Value	Language
dc.contributor.author	Kant, Rama	-
dc.contributor.author	Rangarajan, S.K.	-
dc.date.accessioned	2007-06-11T09:49:28Z	-
dc.date.available	2007-06-11T09:49:28Z	-
dc.date.issued	2003-07	-
dc.identifier.citation	Journal of Electroanalytical Chemistry, 2003, Vol.552, p141-151	en
dc.identifier.issn	0022-0728	-
dc.identifier.uri	http://hdl.handle.net/2289/2728	-
dc.description	Restricted Access.	en
dc.description.abstract	We develop a theory for the electrical admittance of a rough interface under diffusion-limited and partial diffusion-limited charge transfer conditions. The large and small-frequency expansion brings out the relationships between the various morphological features of the rough electrode i.e. area, curvature and width, and the average admittance. The diffusion-limited reaction admittance is determined on an approximately self-affine corrugated random surface fractal. We obtain exact results for the low roughness and the asymptotic results (in three frequency regions) for the arbitrary and large roughness surfaces. These results show an anomalous frequency dependence for the mean admittance and the mean excess admittance for the large and small roughness surfaces, respectively. The intermediate frequency behavior of the reaction admittance for small roughness interfaces has the following form: left angle bracketYright-pointing angle bracketnot, vert, similar(iω)1/2+const.(iω)3/2−H, where H is Hurst's exponent, for the large roughness interfaces it has same form as predicted earlier: left angle bracketYright-pointing angle bracketnot, vert, similar(iω)1−H/2. This non-universality and dependence of intermediate-frequency behavior on the strength of interfacial fractality has not been previously conceived. We also show the localization of the active zones in the presence of roughness. Finally, these results unravel the connection between the total reaction admittance and the crossover frequency to the roughness characteristics likes the fractal dimension, lower and upper fractal cutoff lengths, and the amplitude of the fluctuations of the fractal.	en
dc.format.extent	315204 bytes	-
dc.format.mimetype	application/pdf	-
dc.language.iso	en	en
dc.publisher	Elsevier B.V.	en
dc.relation.uri	http://dx.doi.org/10.1016/S0022-0728(03)00039-1	en
dc.rights	2003 Elsevier B.V.	en
dc.subject	Reaction–diffusion impedance	en
dc.subject	Rough electrode	en
dc.subject	Self-affine fractal	en
dc.title	Effect of surface roughness on interfacial reaction–diffusion admittance	en
dc.type	Article	en
Appears in Collections:	Research Papers (TP)

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