The nonspherical or angle dependent part of the intermolecular potential can be studied by a variety of experimental techniques which give direct information about the nonspherical interaction between molecules. In this paper an attempt is made to assess information available on the angle dependent part of the intermolecular potential obtained from acoustical relaxation, NMR, depolarized Rayleigh scattering, flow birefringence, field effects on transport properties of gases and pressure broadening. This information, obtained for simple polyatomic molecules such as N2, CO , H2, HD and CH 4 , is tabulated as effective cross sections which are matrix elements of a collision operator. The results are discussed from two points of view: the experimentally observed trends which the cross sections tend to follow; the ability of theory to agree and predict such trends and to find relationships between cross sections.