Optical phonons of NdBaCo2O5+x: lattice dynamics calculations

Optical phonons (k approximate to 0) of the double perovskite NdBaCo2O5+x are calculated in the cases of x = 0, 1 (tetragonal P4/mmm, a = b = a(p), c approximate to 2a(p)) and x = 0 5 (orthorhombic Pmmm, a = a(p), b approximate to 2a(p), c approximate to 2a(p)) using the shell model The calculated modes in the three crystal structures are classified according to their symmetry and frequency By analyzing the eigenvectors for different modes the most intense bands in the Raman spectra of the complex compound NdBaCo2O5+x are predicted.