Single-valued DMBE potential energy surface for HSO: A distributed n-body polynomial approach

An accurate single-valued double many-body expansion (DMBE) potential energ y surface is reported for the ground electronic state of HSO based on novel MR CISD ab initio energies suitably corrected for the complete one-electro n basis set/complete CI limit. To improve the accuracy of the fit, we have suggested a n-body distributed polynomial approach which implies using indi vidual multinomial developments at the various stationary points. For simpl icity, only the three most relevant such points have been considered: two m inima (HSO, HOS) and the saddle point connecting them.