In order to clarify systematic trends of governing outer shape of molecules, isopotential energy contours of hydrogen and nitrogen molecules as probed by ground-state atoms from H to Ar have been studied. Periodicity and some interesting patterns have been found for the outer profiles of molecules. When the exchange repulsion energy is dominant, repulsive walls of potential energy curves show a simple exponential decay with hardness depending on the ionization potentials. When anisotropic interactions reduce the exchange repulsion energy effectively, outer shape of molecules probed by atoms are deformed into various farms, even for simple diatomic molecules such as hydrogen and nitrogen.