A Calculation of the H₂o₂ Molecule by the Lcao–mo–scf Method

The electronic structure of the hydrogen peroxide molecule in three different configurations, namely the cis, the trans, and the non-planar or skew forms, were calculated according to the LCAO–MO–SCF approximation. All the electrons were considered except those of the K-shell of the oxygen atoms. The orbitals of these atoms are essentially of the sp 3 hybrid type. It was shown that the skew form of the molecule with an azimuthal angle Φ of about 120° is the most stable, due mainly to conjugation of the σ 5 and σ 6 orbitals of the oxygen atoms with the other molecular orbitals. On the contrary, in the cis and trans forms these two orbitals are non-bonding. Because of the approximate nature of the treatment, especially as regards the screening effect of the K-electrons, the calculated orbital energies are definitely too large. However, the heights found for the cis and the trans barriers are in a reasonable mutual ratio. Numerical values were also obtained for the ionization potentials and the dipole moment of the skew model; the latter result, 2.05 D, agrees well with the experimental data.