Variational theory for a single polyelectrolyte chain revisited

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dc.creatorManghi, Manoel
dc.creatorNetz, Roland R.
dc.date2004-06-02
dc.date.accessioned2026-07-07T06:25:55Z
dc.date.available2026-07-07T06:25:55Z
dc.descriptionWe reconsider the electrostatic contribution to the persistence length, $\ell_e$, of a single, infinitely long charged polymer in the presence of screening. A Gaussian variational method is employed, taking $\ell_e$ as the only variational parameter. For weakly charged and flexible chains, crumpling occurs at small length scales because conformational fluctuations overcome electrostatic repulsion. The electrostatic persistence length depends on the square of the screening length, $\ell_e\simκ^{-2}$, as first argued by Khokhlov and Khachaturian by applying the Odijk-Skolnick-Fixman (OSF) theory to a string of crumpled blobs. We compare our approach to previous theoretical works (including variational formulations) and show that the result $\ell_e\simκ^{-1}$ found by several authors comes from the improper use of a cutoff at small length scales. For highly charged and stiff chains, crumpling does not occur; here we recover the OSF result and validate the perturbative calculation for slightly bent rods.
dc.description11 pages, 6 figures
dc.identifierhttps://arxiv.org/abs/cond-mat/0406059
dc.identifierhttp://arxiv.org/abs/cond-mat/0406059
dc.identifierEuropean Physical Journal E (2004) vol. 14, issue 1, pages 67-77
dc.identifierdoi:10.1140/epje/i2004-10007-3
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/96966
dc.subjectSoft Condensed Matter
dc.subjectStatistical Mechanics
dc.titleVariational theory for a single polyelectrolyte chain revisited
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