After obtaining a free energy of Gibbs or optimization geometry using AMBER/ AM1 methods, we can plot two-dimensional contour diagrams of the electrostatic potential surrounding a molecule, the total electronic density, the spin density, one or more molecular orbitals, and the electron densities of individual orbitals.

HyperChem software displays the electrostatic potential as a contour plot when you select the appropriate option in the Contour Plot dialog box. Choose the val­ues for the starting contour and the contour increment so that you can observe the
minimum (typically about -0.5 for polar organic molecules) and so that the zero potential line appears.

A menu plot molecular graph, the electrostatic potential property is selected and then the 3D representation mapped isosurface for both methods of analysis. Atomic charges indicate where large negative values (sites for electrophilic attack) are likely to occur.