Dynamical properties of the spin-Peierls compound α'-NaV_2O_5

Dynamical properties of the novel inorganic spin-Peierls compound \alpha'-NaV_2O_5 are investigated using a one-dimensional dimerized Heisenberg model. By exact diagonalizations of chains with up to 28 sites, supplemented by a finite-size scaling analysis, the dimerization parameter $\delta$ is determined by requiring that the model reproduces the experimentally observed spin gap $\Delta$. The dynamical and static spin structure factors are calculated. As for CuGeO_3, the existence of a low energy magnon branch separated from the continuum is predicted. The present calculations also suggest that a large magnetic Raman scattering intensity should appear above an energy threshold of $1.9 \Delta$. The predicted photoemission spectrum is qualitatively similar to results for an undimerized chain due to the presence of sizable short-range antiferromagnetic correlations.