The calculation of resonances by an L² method; rotational resonances of H₂Ar

Abstract

A method is proposed for calculating the positions and widths of resonances, using an L ² basis set. A variational calculation with such basis yields a discretized resonance phase shift. The resonance parameters are obtained by a fit of this phase shift to a Breit-Wigner curve. The accuracy of the method, which is generally applicable, is tested on the rotational resonances of the van der Waals complex H₂Ar, using a number of different basis sets. The method is very fast and yields fairly accurate results for both the positions and the widths of the resonances.