The spectrum and ground state potential curve of Ar2

The absorption spectrum of Ar2 has been photographed at a dispersion sufficiently high to allow a rotational analysis of one band system. From the analysis, the vibrational and rotational constants of the five lowest vibrational levels of the ground state have been determined. These spectroscopic data, together with information from long-range forces and from the second virial coefficient, have been used to calculate the potential curve of the ground state. This calculated curve is compared with other curves which have been proposed.