Rotational Barriers in Hydrogen Peroxide

The rotational barriers in hydrogen peroxide are investigated using LC(Hartree–Fock) AO MO SCF calculations. Systematic improvement of the basis set produces a definite trans barrier, demonstrating that this barrier, like all those previously studied, is calculable within the Hartree–Fock approximation. Allowance for geometry adjustment, particularly OOH angle variation, leads to a cis barrier much closer to agreement with experiment than that obtained assuming rigid rotation. The theoretical and experimental inplications of these findings are discussed.