Analyzing Kullback-Leibler information profiles: an indication of their chemical relevance

The Kullback-Leibler information deficiency is evaluated along molecular internal rotational or vibrational coordinates and along the intrinsic reaction coordinate for several reactions (intra- and intermolecular proton transfer and S(N)2 reaction). For the first time an in depth analysis of the information deficiency along the reaction path is reported. The results are consistent with the Hammond postulate, indicating that the information profiles contain relevant chemical information. A local version of the information deficiency is defined by considering Hirshfeld's partitioning of atoms in molecules. The analysis of the local information profiles permits the identification of the atoms taking part in the electron reorganization processes.