Delimitation of the frontier behaviour domain between gas/liquid of some cryogenics substances

The study is dealing with the delimitation of the gas/liquid behaviour in the domain of specific volumes less than critical. The analysis was done using the Lennard-J potential, in reduced coordinates, to take into account the behaviour of substance between the critical point and point of maximum intermolecular force. For obtaining accurate data the argon has been accepted as reference. The delimitation of the gas/liquid behaviour through transition domain defined from the reduced specific volume of the critical point and the point of maximum intermolecular force will be proposed. The study is available for He, Ne, Ar, Kr, Xe, N2, O2, CO, CH4, which are substances of interest in cryogenics. (author)