A New Model Potential Acting on the Excited Electron Within Molecules: Application to Calculate the Recurrence Spectra of Excited H₂ Molecules in Strong External Fields

By using the molecular orbit theory, we give a new model potential acting on the excited electron within a molecule. The potential is the total interaction energy of this electron with all the nuclei and other electrons. We find that the introduction of a new model potential results in an extreme increase of the number of closed orbits as compared to the hydrogen atom. Making use of the molecular closed-orbit theory (MCOT) and the new model potential, we calculate the recurrence spectra of H₂ molecules in parallel electric and magnetic fields for different quantum defects. The modulations in the spectra can be analysed in terms of the scattering of the excited electron on the molecular core. Our results are in good agreement with the quantum results.