title: Order of the phase transition in models of DNA thermal denaturation.
abstract: We examine the behavior of a model which describes the melting of double-stranded DNA chains. The model, with displacement-dependent stiffness constants and a Morse on-site potential, is analyzed numerically; depending on the stiffness parameter, it is shown to have either (i) a second-order transition with nu( perpendicular) = -beta = 1,nu(||) = gamma/2 = 2 (characteristic of short-range attractive part of the Morse potential) or (ii) a first-order transition with finite melting entropy, discontinuous fraction of bound pairs, divergent correlation lengths, and critical exponents nu( perpendicular) = -beta = 1/2,nu(||) = gamma/2 = 1.
authors.affiliation: Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Vasileos Constantinou 48, 116 35 Athens, Greece.
authors.forename: N
authors.initials: N
authors.lastname: Theodorakopoulos
authors.forename: T
authors.initials: T
authors.lastname: Dauxois
authors.forename: M
authors.initials: M
authors.lastname: Peyrard
mesh_terms: D004247:DNA / Q000737:chemistry*; D019277:Entropy; D006358:Hot Temperature; D008956:Models, Chemical; D009691:Nucleic Acid Denaturation; D013816:Thermodynamics
chemical_list: D004247:DNA