Predictive model for the intra-diffusion coefficients of H₂ and O₂ in vapour H₂O based on data from molecular dynamics simulations

ABSTRACT

Available data from experiments and molecular simulations for the intra-diffusivities of H${}_2$ and O${}_2$ in H${}_2$O, and for the self-diffusivity of pure H${}_2$O (at pressure and temperature conditions in which the solvent is in the vapour phase) are compared against calculations based on the Chapman-Enskog theory or other semi-empirical/semi-theoretical methods. A novel methodology is proposed to extrapolate the intra-/self-diffusivities data computed from molecular dynamics simulations at low pressures. The extrapolated values are used to further refine the recently-proposed [Tsimpanogiannis et al., J. Chem. Eng. Data, 66, 3226-3244, (2021)], molecular simulation based correlation of intra-/self-diffusivities as a function of pressure and temperature with the solvent being in the vapour phase.

GRAPHICAL ABSTRACT

KEYWORDS:

• Chapman-Enskog theory
• hydrogen
• oxygen
• molecular dynamics
• diffusion in water

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was also sponsored by NWO Domain Science for the use of supercomputer facilities.