Calculations are reported concerning the structure of the anthracene stable dimer. It is shown that the use of an ‘exp-6’ atom-atom potential produces a structure which is definitely not that allowed by the experimental data : this is shown to be due to the absence of any simulation of permanent moment interactions in the atom-atom potentials. A number of conventional methods for calculating the individual terms of the total potential energy are used to estimate the magnitudes of these terms. It is concluded that the resulting relative magnitudes of the individual terms cannot be determined accurately enough to justify the construction of a total potential energy curve. However, by considering the variation of the individual terms with the relative orientation of the two molecules of the dimer, the dominant role of the quadrupole-quadrupole terms in determining the dimer structure is clearly demonstrated.