Non-equilibrium umbrella sampling applied to force spectroscopy of soft matter

Date

2012-02-01

Authors

Gao, Y. X.
Wang, G. M.
Williams, D. R. M.
Williams, Stephen R.
Evans, Denis J.
Sevick, E. M.

Journal Title

Journal ISSN

Volume Title

Publisher

American Institute of Physics (AIP)

Abstract

Physical systems often respond on a timescale which is longer than that of the measurement. This is particularly true in soft matter where direct experimental measurement, for example in force spectroscopy, drives the soft system out of equilibrium and provides a non-equilibrium measure. Here we demonstrate experimentally for the first time that equilibrium physical quantities (such as the mean square displacement) can be obtained from non-equilibrium measurements via umbrella sampling. Our model experimental system is a bead fluctuating in a time-varying optical trap. We also show this for simulated force spectroscopy on a complex soft molecule--a piston-rotaxane.

Description

Keywords

colloids, rotaxanes, microscopy, atomic force

Citation

Source

The Journal of Chemical Physics

Type

Journal article

Book Title

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