The acetyl cation and its geometrical isomers

Abstract
Ab initio self‐consistent‐field (SCF) calculations are reported on the acetyl cation (CH3CO+) and three of its possible geometrical isomers. The wavefunctions are discussed in terms of Mulliken populations and simple valence bond arguments. The energies of the low‐lying electronic states of CH3CO+ are estimated and compared with those of CO. The similarities and differences are explained in terms of simple chemical arguments. Finally an accurate two configuration wavefunction for the CH3CO+ fragmentation is presented, showing unambiguously the dissciation products to be the expected ones, CH3+ and CO.