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Stretching a macromolecule in an atomic force microscope: statistical mechanical analysis.

H J Kreuzer·S H Payne
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Abstract

We formulate the proper statistical mechanics to describe the stretching of a macromolecule under a force provided by the cantilever of an atomic force microscope. In the limit of a soft cantilever the generalized ensemble of the coupled molecule/cantilever system reduces to the Gibbs ensemble for an isolated molecule subject to a constant force in which the extension is fluctuating. For a stiff cantilever we obtain the Helmholtz ensemble for an isolated molecule held at a fixed extension with the force fluctuating. Numerical examples are given for poly (ethylene glycol) chains.

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Biophysical PhenomenaBiophysicsMacromolecular SubstancesMicroscopy, Atomic ForceModels, StatisticalModels, TheoreticalStatistics as TopicJournal Article

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BibTeXRIS

H J Kreuzer, S H Payne. 2001-01-23. Stretching a macromolecule in an atomic force microscope: statistical mechanical analysis.. https://doi.org/10.1103/physreve.63.021906

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