An iterative Bloch approach to the resonance state problem

This paper proposes a new Gauss–Seidel Bloch formulation of the degenerate eigenvalue problem. The algorithm is designed to be applicable to large vector spaces; it only requires the presence in core memory of the few vectors which constitute the degenerate subspace. The theory is applied to the resonance states of the linear van der Waals complexes I2–X(X=Ar,Ne,He). Partial widths and branching ratios are determined by analyzing the asymptotic outgoing flux transported by the quasibound states in the various open channels. The comparison with previous close-coupling results reveals the efficiency of the method for resolving the resonance eigenvalue problem.