First-principles Raman studies on YBa2Cu3O7

We have investigated all Raman-active phonon modes (A(1g), B-2g, and B-3g s ymmetry) of YBa2Cu3O7 by first principles LAPW calculations based on densit y functional theory. We demonstrate that an excellent overall agreement bet ween measured and calculated phonon frequencies can only be achieved on the basis of a fully optimized crystal structure. The Raman scattering intensi ties for the A(1g) modes are determined. Due to a strongly decreased admixt ure of apical oxygen in the eigenvector of the O2-O3 mode with respect to p reviously published results the discrepancy between theory and experiment i n the resonance profile of this mode is lifted.