Evolution of the Atomic and Bond Properties of Hydrogen Peroxide During Internal Rotation

The evolution of the atomic and bond properties of hydrogen peroxide during H–O–O–H internal rotation was studied by means of Atoms in Molecules Theory. Wave functions obtained at several calculation levels were employed to test the reliability of the results. These levels included HF, MP2, QCISD, and B3LYP carried out with several basis sets. All the calculations show that the bondpath connecting the two oxygen atoms is a bent line, whose shape and orientation display a large variation along the internal rotation. The different calculation levels predict a very similar evolution for each property. We observed that the calculation level does not introduce important changes in the absolute values of the properties studied here, but comparisons between results provided by wave functions obtained after a geometry optimization carried out at an electron correlated level and results obtained after a HF geometry optimization. It was found that electron correlation provides lower electron populations and higher kinetic energies for the oxygen fragments in every conformation.