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Felix Hanke

Publications and source records attributed to Felix Hanke.

2 recordsLinked to original sources

Breaking bonds in the atomic force microscope: theory and analysis.

A theoretical framework is developed to analyze molecular bond breaking in dynamic force spectroscopy using atomic force microscopy. An analytic expression of the observed bond breaking probability as a function of force is obtained in terms of the relevant physical parameters. The force-ramp mode is discussed in detail, which gives the best framework to extract the relevant physical parameters such as the potential depth and its width, if a set of widely different force-loading rates are used. We also show that the commonly used Ritchie-Evans model is incomplete and that it is only applicable for forces well below the maximum permitted by the potential. Statistical complications arising from the use of constant velocity experiments are discussed in detail.

Microscopy, Atomic Force↗

Nonequilibrium theory of polymer stretching based on the master equation.

We present a model for fast polymer-stretching experiments. We use the master equation and argue that the end-to-end extension of a polymer molecule can be used as a stochastic variable after appropriate coarse graining. The main effect of increasing pulling speed or force loading rate is a marked hysteresis in the force-extension curve as well as an overall shift of the curve to higher forces when compared to the equilibrium curve. This can be understood in terms of the moments of the transition probability in the master equation. An analysis of the fluctuations and relaxation times is also given in the framework of our theory.

Journal Article↗