NON-ANALYTICITY OF SELF-CONSISTENT FIELD APPROACHES - FAILURE OF PREDICTING SYMMETRY

It is found that the Fock operator is not necessarily dilatation analytic in symmetry changing situations. This leads to an unreliability of self-consistent fields to predict symmetry (e.g., the correct point group of a molecule). The analysis shows that the non-analyticity is particularly relevant for open-shell systems. Possibilities to circumvent these difficulties are briefly mentioned. The discussion applies also to the complex rotation method. © 1990 IOP Publishing Ltd.