Abstract:
We report the results of an analysis of the vibrational properties of the apical oxygen O(4) in YBa2Cu3O6+x as a function of the the oxygen concentration O(1) in the chains. The analysis is based on the calculation of the behaviour of the partial phonon density of states for O(4) for different x values. Following the movement of the peaks corresponding to different modes we pay special attention to the discussion of possible anomalous displacement of the apical oxygen in the c direction.