Relative stability of the2 A 1g and2 E g states of the C2H 6 + ion

Anab initio study of the relative stability for the states²A_1g and²E_g of C₂H₆⁺ has been carried out. The results of the Open Shell Restricted Hartree-Fock calculations lead to assign the²A_1g as the ground state of the molecule in agreement with previous SCF calculations.The correlation energy associated to both states has been calculated within the correlation hole model and the results, contrary to those obtained from Configuration Interaction calculations, do not alter qualitatively the conclusions from SCF.