Equation of State of 20Ne gas in the temperature-range 27-36 K

The many-body phase shifts for 20Ne gas are calculated for low number densities in the temperature-range 27-36 K, using the Galitskii-Migdal-Feynman formalism. These phase shifts are inserted in the Beth-Uhlenbeck formula to determine the quantum second virial coefficient. This is compared to the classical coefficient as well as to the experimental values and other theoretical results. It is used to investigate the pressure-volume-temperature behavior of the gas and to compute other thermodynamic properties - the Helmholtz free energy, total internal energy, entropy, and specific heat capacity - for a number density of 1× 1027 atoms/m3. Our results show that, in cooling and compressing the system, vapor-liquid condensation always occurs.