Resonances in inelastic collisions: decay widths and patterns for resonance states

We consider a multichannel scattering system with compound state (Feshbach) resonances originating from continuum embedded bound states under perturba- tion and analyse the structure of the scattering wave function in the interaction region. An extension of the Fano formalism yields a representation of the wave func- tion as a mixture of the unperturbed bound state and scattering states characterized by an energy-depending mixing phase. The nodal pattern of the wave function inside the interaction region changes rapidly with the energy near the resonance. This change occurs on an energy scale which does not correspond to the resonance width and can be much broader. The theoretical predic- tions are applied to a collinear collision model and com- pared with numerical results.