[en] For the systems Na(3 ²P/sub 3/2/)Ar, NaKr, and NaXe we have measured the total differential cross sections at thermal energies. All systems show a well resolved oscillation structure of the cross sections. For these data quantum mechanical calculations have been performed based on pseudopotentials (for NaAr), and calculations in the elastic WKB approximation using a Lennard-Jones (8,6) potential (for NaAr, NaKr, and NaXe). The results allow us to determine the interatomic potentials with high accuracy. A comparison is made by a detailed listing of experimental and theoretical results published up to now