pi-pi-interaction ?

     Dear all,
     in  "Semiempirical Molecular Orbital Methods" (Rev.Comp.Chem.
     2(1990)pp 45-81)    J.J.P. Stewart describes 'strong and weak points
     of NDDO semiempirical methods'.
     What I am interested in is whether there is any further reference
     regarding the value of semiempiric methods (AM1, PM3, also ZINDO-1)
     especially for the description of intermolecular pi-pi interaction
     of aromatic molecules.
     I would appreciate any hint on reported results or experience with
     that, will summarize if it seems appropriate.
     Michael Neuber
     [ AT ] Berlin