  We report on a direct method to measure the internuclear potential energy
curve of diatomic systems. A COLTRIMS reaction microscope was used to measure
the squares of the vibrational wave functions of H$_{2}$, He$_{2}$, Ne$_{2}$,
and Ar$_{2}$. The Schr\"odinger equation relates the curvature of the wave
function to the potential V(R) and therefore offers a simple but elegant way to
extract the shape of the potential.
