A non-empirical LCAO-SCF-MO investigation of cross sections through the potential energy surface for the [C2H2Cl]+ systems; comparison with the [C2H5+] and [C2H4F]+ systems

Non-empirical LCAO MO SCF calculations are reported on cross sections through the C₂H₄Cl⁺ system and comparisons are drawn with the C₂H₅⁺ and C₂H₄F⁺ systems. Barriers to rotation in the classical 1- and 2-substituted ethyl cations have been computed and an investigation made of the bridged chloronium and fluoronium ions. The results suggest that the relative stabilities of bridged ions with respect to the corresponding classical 2-substituted ethyl cations increase in the order H < F < Cl. The results are discussed in terms of available experimental data and consideration given to correlation and solvation energy effects.