Electrostatic potentials show the distribution of electronic charge on the molecule. The colors represent the charge distribution. In this case, the blue represents the most positively-charged regions, and the reds show the most negatively-charged regions. As one might predict, the negative charge is found mostly around the oxygen atoms, and the more positive regions are found near the hydrogen atoms.
The three visualizations show the same molecule. The first visualization shows the electrostatic potential as mapped onto the electron density of the molecule. The electron density gives a good idea of the shape of the molecule. The second visualization shows the electrostatic potential as a mesh, so that the user can see the molecule inside the electron density. Likewise,the third visualization shows the electrostatic potential mapped onto a transparent electron density.
Finally, the last visualization shows a movie of the molecule with the electrostatic potential and the electron density shown as dots, and rotated around so the user can see the molecule from all perspectives.
