DFT vibrationally averaged isotopic dipole moments of propane, propyne and water isotopologues

Post Born–Oppenheimer isotopic effects and zero-point vibrational averages were previously inbodied in calculations of the dipole moments of isotopic species of some apolar molecules within the HF-SCF approximation (Arapiraca, 2011) [27]. Many other molecules, however, demand the inclusion of electronic correlation for this goal. Here, DFT calculations are reported for the isotopic effects on dipole moments of molecules with increasing permanent dipole moments, namely propane ( μ ≃ 0.1 debye), propyne ( μ ≃ 0.7 debye) and water ( μ ≃ 1.9 debye). The results account well for the experimental values and isotopic trends of the dipole moments of these molecules.