We consider the wave dynamics of a one-dimensional lattice where both on-site and inter-site vibrations, coupled together, are governed by Morse interactions. We focus attention on the onset of lattice solitons and discrete breathers (DBs, aka intrinsic localized modes, ILM). We show how varying the relative strength of the on-site potential to that of the inter-site potential permits transition from one mode of (travelling or otherwise) localized excitation to the other.
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