We study the resonances of matrix Schrödinger operators, motivated by the Born-Oppenheimer approximation. We give a simple criterion for the potential to generate resonances. This criterion also gives the location of the resonances generated.
"Resonances for matrix Schrödinger operators." Duke Math. J. 106 (2) 209 - 236, 1 February 2001. https://doi.org/10.1215/S0012-7094-01-10621-2