SELF-CONSISTENT-PHONON-APPROXIMATION STUDY OF A DOUBLE MORSE HYDROGEN-BONDED CHAIN

We propose a one-dimensional hydrogen-bonded chain model, where temper ature is introduced using a variational form of the self-consistent-ph onon-approximation method to evlauate the semiquantum free energy. The parameters of the model are chosen self-consistently and the hydrogen bond is described by a double Morse interaction. The behavior of the chain is studied with a defect and without one and the Peierls barrier is calculated. Introduction of an anharmonic O-O interaction results in slight qualitative changes.