AB-INITIO MO STUDY ON C4O - STRUCTURES AND ELECTRON-AFFINITIES

The geometrical structures of four conformers of the C4O molecule were surveyed with second- and third-order Moller-Plesset perturbation the ory and complete active space SCF methods using the Huzinaga-Dunning d ouble zeta plus polarization basis set. The relative stability of the conformers and the electron affinity Of C4O were calculated by the con figuration interaction method (including single and double excitations ) with the Davidson correction. The general contraction scheme of the [5s4p2d1f] atomic natural orbital basis set, based on the (14s9p4d3f) primitive Gaussian functions, was applied. The linear structure is mos t stable in both neutral and anionic C4O. The electron affinity Of C4O was calculated to be 2.77 eV, 0.72 eV larger than the experimental va lue.