Calculations of solid‐state data of neon, and the vapour pressure ratio of its isotopesf

Calculations have been made of the free energies and equations of state of solid 20Ne and 22Ne, using the method of Henkel. The vapour pressure ratio of the neon isotopes' deduced from the calculated difference in their free energies is in excellent agreement with experimental measurements. Although the molecular volumes of the two isotopes differ by about 0–5%, the vapour pressure ratio can be calculated quite accurately on the assumption that there is no such volume effect; the reasons for this are explained.