Calculated Diffusivities for Water Isotopologues in Nitrogen, Oxygen, and Air

Values are computed for the dilute-gas diffusivity of water isotopologues in N2, O2, and their mixture at a composition representing air, for standard conditions of 101.325 kPa and water mole fraction approaching zero. Calculations employ state-of-the-art intermolecular potentials and classical trajectory calculations as described in the paper by R. Hellmann and A.H. Harvey, "First-Principles Diffusivity Ratios for Kinetic Isotope Fractionation of Water in Air", published in Geophysical Research Letters volume 47, issue 18, article e2020GL089999 (2020), https://doi.org/10.1029/2020GL089999. Separate files are given for the diffusivities of H2O, HDO (where D is deuterium), and the 17-O and 18-O substitutions of H2O.