The diffusion mechanism of an excess proton in imidazole molecule chains: first results of an ab initio molecular dynamics study

The diffusion mechanism of an excess proton in imidazole molecule chains is studied by Car–Parrinello-type ab initio molecular dynamics simulations. The diffusion process is described by a Grotthuss mechanism (structure diffusion) involving proton transfer and local rather than long-range cooperativ...

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Bibliographic Details
Published in:Solid state ionics 2001-12, Vol.145 (1), p.437-443
Main Authors: Münch, W, Kreuer, K.-D, Silvestri, W, Maier, J, Seifert, G
Format: Article
Language:English
Subjects:
Ab initio molecular dynamics
Condensed matter: structure, mechanical and thermal properties
Diffusion in solids
Exact sciences and technology
Imidazole
Numerical simulations
Physics
Proton conductivity
Proton diffusion mechanism
Self-diffusion and ionic conduction in nonmetals
Transport properties of condensed matter (nonelectronic)
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Summary:The diffusion mechanism of an excess proton in imidazole molecule chains is studied by Car–Parrinello-type ab initio molecular dynamics simulations. The diffusion process is described by a Grotthuss mechanism (structure diffusion) involving proton transfer and local rather than long-range cooperative reorientation of the imidazole chain. At T=390 K, the proton transfer step is found to be fast with a time scale of 0.3 ps. The reorientation step is found to be rate-determining. According to our model, the time scale for the reorientation step is estimated to be approximately 30 ps in this temperature range.
ISSN:0167-2738
1872-7689
DOI:10.1016/S0167-2738(01)00941-9