| Abstract: | Ab initio SCF calculations are reported for the potential surfaces of the HCO+ and COH+ molecular ions in both ground and low-lying excited states. An analysis of the bonding characteristics of the two systems is undertaken, from which it is noted that the 5σ and 1π orbital energy levels in HCO+ are inverted relative to the order found in both COH+ and also in CO itself. This fact leads to a situation in which the (1π, 2π) excited states of HCO+ as well as the ground state are more stable than their COH+ counterparts, whereas the opposite relationship is observed for (5σ, 2π) species. In addition it is pointed out that those states which populate the 7a' in-plane component of the 2π MO in either molecule-ion are characterized both by bent equilibrium structures and also by dissociation into CO+ + H, whereas all other low-lying species, including the ground state, prefer linear structures which dissociate via a CO + H+ channel. |
