Stretching a macromolecule in an atomic force microscope: Statistical mechanical analysis - art. no. 021906

Citation
Hj. Kreuzer et Sh. Payne, Stretching a macromolecule in an atomic force microscope: Statistical mechanical analysis - art. no. 021906, PHYS REV E, 6302(2), 2001, pp. 1906
Citations number
13
Categorie Soggetti
Physics
Journal title
PHYSICAL REVIEW E
ISSN journal
1063651X → ACNP
Volume
6302
Issue
2
Year of publication
2001
Part
1
Database
ISI
SICI code
1063-651X(200102)6302:2<1906:SAMIAA>2.0.ZU;2-N
Abstract
We formulate the proper statistical mechanics to describe the stretching of a macromolecule under a force provided by the cantilever of an atomic forc e microscope. In the limit of a soft cantilever the generalized ensemble of the coupled molecule/cantilever system reduces to the Gibbs ensemble for a n isolated molecule subject to a constant force in which the extension is f luctuating. For a stiff cantilever we obtain the Helmholtz ensemble for an isolated molecule held at a fixed extension with the force fluctuating. Num erical examples are given for poly (ethylene glycol) chains.