ENTROPY-DRIVEN DNA DENATURATION

We present a nonlinear dynamical model for DNA denaturation which incl udes cooperativity effects through anharmonic nearest-neighbor stackin g interactions. Transfer-integral calculations show that this one-dime nsional model, without including long-range interactions, exhibits a s harp denaturation reminiscent of a first-order transition at a tempera ture lower than a similar model with harmonic coupling. Self-consisten t phonon calculations point out the essential role of nonlinear effect s in the mechanism.