Geometries and potential energies for reactants of "H-Cl-Cl" around the transition state in the reaction of H + Cl2 → HCl + Cl were calculated. The reactant on the transition state was formed at incident angle of 180°. This reactant was supported by the method of the intrinsic reaction coordinate (IRC). We produced a movie, which displays CGs of potential energy surfaces in 2-D and 3-D for reactants on the way of the reaction. The reaction profile with potential energy and structures of the reactants are also displayed. The profile was synchronized with the structures. The CG movie was tried, and it was improved through the application to student's learning on the Web. It was effective for students to acquire images of the reaction from the standpoint of its potential energy and molecular structure.
Computational chemistry programs were evaluated as aids to teaching qualitative analytical chemistry. Computational chemical calculations can predict absorption spectra, thus enabling the modeling of indicator dissociation mechanisms by different computational chemical programs using a personal computer. An updated MNDO program among 51 programs was found to be the best predictor to explain the dissociation mechanisms of isobenzofuranones and sulfonephthaleins. Unknown dissociation constants were predicted from atomic partial charges instead of Hammett's constants.