DNA DENATURATION FOR A TANGLED CHAIN

We have considered a model of a lattice gas defined on a periodic tang led chain to study the DNA denaturation by a modified transfer matrix method. By using an iterative algorithm we have obtained numerically d ifferent kinds of melting curves for different configurations of the t angled chain and different types of interactions. In some special case s of configurations and interactions we have found the same melting cu rves, which we have obtained before studying some simple lattice gas m odels, using different techniques. This more generalized model and the new results could be useful for the experimental investigations.