Foundations and recent developments on molecular quantum similarity

A general definition of the Quantum Molecular Similarity Measure is reported. Particular cases of this definition are discussed, drawing special attention to the new definition of Gravitational-like Quantum Molecular Similarity Measures. Applications to the study of fluoromethanes and chloromethanes, the Carbonic Anhydrase enzyme, and the Hammond postulate are presented. Our calculations fully support the use of Quantum Molecular Similarity Measures as an efficient molecular engineering tool in order to predict physical properties, biological and pharmacological activities, as well as to interpret complex chemical problems.