AN ITERATIVE BLOCH APPROACH TO THE RESONANCE STATE PROBLEM

This paper proposes a new Gauss-Seidel Bloch formulation of the degene rate 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 i s applied to the resonance states of the linear van der Waals complexe s I2-X(X =Ar,Ne,He). Partial widths and branching ratios are determine d by analyzing the asymptotic outgoing flux transported by the quasibo und states in the various open channels. The comparison with previous close-coupling results reveals the efficiency of the method for resolv ing the resonance eigenvalue problem.