A Comparative Study of Electrostatic Similarity Indices
Črtomir Podlipnik, Jože Koller · Hrčak Portal of scientific journals of Croatia (University Computing Centre) · 1998
In this study, the ethanol molecule was superimposed on a set of molecules (ethane, ethantiol, ethilamine, methanol, propane and water). Similarity, on the basis of the molecular electrostatic potential (MEP), was evaluated on the semiempirical AM1 and HF/6–31+G* . The Carbo index was used as a measure of similarity and three different formalisms were used for similarity evaluations: the MEP by the grid method, the ESP charge by the grid method and the ESP charge by the Gaussian approximation. It was found that the choice of the MO method and formalism do not play an important role when indices are high. When we superimpose two electrostatic potentials of molecules that are not similar, as for example electrostatic potentials of ethanol and ethane, the Gaussian approximation gives evidently higher values of the similarity indices than the grid method.