Calculated and observed isotope effects with easily polarizable hydrogen and deuterium bonds

Abstract

On the basis of former ab initio calculations on H₅O⁺ ₂, the deuterium bond of D₅O⁺ ₂ is treated by considering vibrations in two dimensions. Vibrational energy levels, intensities and polarizabilities dependent on the electrical field strengths at the deuterium bond are calculated for a variety of bond lengths. From the absorption intensities continuous absorption spectra are calculated, taking into account distributions of electrical field strengths and O–O distances. These continua are compared with i.r. spectra of aqueous solutions of HCl or DCl and H₂SO₄ or D₂SO₄ in H₂O or D₂O, respectively. The calculated isotope factor of the intensity I_νOH/I_νOD, which is dependent on wavenumber, agrees with experimental data.