Using the method of complex scaling we show that scattering resonances of −Δ+V, V∈Lc∞(Rn), are limits of
eigenvalues of −Δ+V−iϵx2 as ϵ→0+. That
justifies a method proposed in computational chemistry and reflects a general
principle for resonances in other settings.Comment: 19 pages, 3 figure