Improved L2-stabilization theory to compute resonances under multichannel conditions

The stabilization theory for the calculation of resonance energies and widths in the version of Mandelshtam, Taylor, Ryaboy and Moiseyev has been applied to collinear ABA molecules in which two Morse potentials are kinetically coupled. This system has about 40 resonances in 10 channels. The results are compared with converged computations by the complex scaling method. Subtracting the background phase of the uncoupled problem (but including the full potential) improves the stabilization calculation appreciably, allowing easier identification of the resonances and better fits of the scattering phase to the arctan-sigmoids, from which the resonance position in the complex plane can be computed.