Structure factor and dynamics of the helix-coil transition

TL;DR

This paper analyzes the helix-coil transition by computing the structure factor and introducing a dynamical model, revealing universal scaling behavior and gelation phenomena near the transition point.

Contribution

It introduces a dynamical model for the helix-coil transition and demonstrates universal scaling and gelation phenomena through analytical and numerical methods.

Findings

Structure factor exhibits universal scaling near transition

Dynamical model predicts gelation above critical temperature

Phenomenological theory agrees with Monte Carlo simulations

Abstract

Thermodynamical properties of the helix-coil transition were successfully described in the past by the model of Lifson, Poland and Sheraga. Here we compute the corresponding structure factor and show that it possesses a universal scaling behavior near the transition point, even when the transition is of first order. Moreover, we introduce a dynamical version of this model, that we solve numerically. A Langevin equation is also proposed to describe the dynamics of the density of hydrogen bonds. Analytical solution of this equation shows dynamical scaling near the critical temperature and predicts a gelation phenomenon above the critical temperature. In the case when comparison of the two dynamical approaches is possible, the predictions of our phenomenological theory agree with the results of the Monte Carlo simulations.