ISOBARIC PROCESSES CLOSE TO THE SPINODAL

We construct a generalized Landau free energy expansion around any spinodal point, for which the usual expansion around the critical point is a particular case. The decay of deeply quenched metastable states close to the spinodal through isobaric processes is analyzed and their mean life time is related to a barrier height, which we compute. The results are compared with those obtained through the use of the usual Landau free energy expansion around the critical point.