### Speaker

### Description

Based on classical statistical mechanics, we calculate analytically the length extension under a pulling force of a polymer modeled as a freely jointed chain (FJC) with extensible bonds, the latter being considered as harmonic springs. We obtain an approximated formula for the extension curve that can reproduce with high precision the extension/force curves also at low values of the elastic constant of the spring, where previous phenomenological proposals differ substantially.

Moreover, a Transfer Matrix based procedure allowed to calculate numerically the extension/force curve of the polymer in the presence of both elastic contribution: the elastic longitudinal harmonic bonds giving the extensibility and the restoring bending between two consecutive bonds. In addition, an analytical expression has been found resulting in the most accurate approximation of the discrete extensible WLC model found at the date.

In all cases, we used the numerical experiments given by Langevin simulations to compare both the analytical results and the phenomenological expressions used in the literature.