Single-molecule stretching experiments of flexible (wormlike) chain molecules in different ensembles: Theory and a potential application of finite chain length effects to nick-counting in DNA

We propose a formalism for deriving force-elongation and elongation-force relations flexible chain molecules from analytical expressions their radial distribution function, which provides insight into the factors controlling asymptotic behavior finite length corrections. In particular, we apply this to our previously developed interpolation formula wormlike end-to-end distance distribution. The resulting expression limit of infinite is similar quality as numerical evaluation Marko's Siggia's variational theory considerably more precise than formula. A comparison data suggests, that finite-chain corrections are quality. As an application results discuss possibility inferring changing number nicks in double-stranded DNA molecule single-molecule stretching experiments accompanying changes effective length.