CONICET | Buscador de Institutos y Recursos Humanos

The resonance states of one- and two-particle Hamiltonians are studied using variationalexpansions with real basis-set functions. The resonance energies, Er, and widths, $Gamma$,are calculated using the density of states and an ${mathcal L}^2$ golden rule-like formula.We present a recipe to select adequately some solutions of the variational problem. The setof approximate energies obtained shows a very regular behaviour with the basis-setsize, N. Indeed, these particular variational eigenvalues show a quite simple scalingbehaviour and convergence when $N igharrow infty$. Following the same prescription tochoose particular solutions of the variational problem we obtain a set of approximatewidths. Using the scaling function that characterizes the behaviour of theapproximate energies as a guide, it is possible to find a very good approximationto the actual value of the resonance width.