First experimental tests of the Peyrard-Bishop model applied to the melting of very short DNAs

The melting curves of short heterogeneous DNA chains in solution are calculated on the basis of statistical thermodynamics and compared to experiments. The computation of the partition function is based on the Peyrard-Bishop hamiltonian, which has already been adopted in the theoretical description of the melting of long DNA chains. In the case of short chains it is necessary to consider not only the breaking of the hydrogen bonds between single base pairs, but also the complete dissociation of the two strands forming the double helix.