Multimagnon excitations in alternating spin/bond chains

The nature of multimagnon excitations in alternating spin/bond ferromagnetic chains are studied using a combination of scaling methods and the recursion method. Two-magnon excitations for a Heisenberg chain with either alternating spin magnitudes, $S$ and $S^{\prime },$ or alternating nearest-neighbor couplings, $J_1$ and $J_2$ can be studied using real-space rescaling techniques. These results are then used to investigate three-magnon excitations using the recursion method.