ℒ2 golden rule method to calculate partial widths for the decay of resonance states

Abstract

We have calculated resonance energies and partial widths for two two‐dimensional models of van der Waals molecule predissociation. We use a general method involving only Hamiltonian and overlap integrals in a square integrable (L ²) basis set containing a scale parameter. We use a stabilization method with a compactness criterion to find the resonance energies, and a decoupled golden rule method to find the partial widths. The results are compared to accurate energies and partial widths obtained by fitting solutions of the close‐coupling equations to multichannel Breit–Wigner expressions. We studied resonances having two open channels for two sets of potential parameters, and in each case we obtained an accuracy of 16% or better for both partial widths by the L ² method.