Concurrent phenomena at the transition region of selected elementary chemical reactions: An information‐theoretical complexity analysis

Abstract

AbstractIn this work, we have investigated in position (r) and momentum (p) spaces the concurrent phenomena occurring at the vicinity of the transition state (TS) (the so‐called transition region) of selected chemical reactions (such as the hydrogenic abstraction and the exchange hydrogenic reactions) by means of a broad set of single information‐theoretic functionals of the one‐particle density (such as the disequilibrium (D), exponential entropy (L), Fisher information (I) and the power entropy (J)) and composite information‐theoretic measures which includes various information planes (such as the I‐D, D‐L, and I‐J planes) and complexities of the Fisher‐Shannon and López‐Mancini‐Calbet (LMC) types. The analysis of the single functionals and the information planes revealed that these information‐theoretical elements can identify all the chemically significant regions, not only the reactant/product regions (R/P) and the TS but also those that are not present in the energy profile, such as the bond cleavage energy region (BCER), the bond breaking/forming regions (B‐B/F) and the charge transfer complex. Moreover, the analysis of the complexities shows that in position as well as in the joint (r‐p) spaces, the energy profile of the abstraction reaction bears the same information‐theoretical features of the LMC and FS measures. Finally, it is shown why most of the chemical features of interest (such as e.g., BCER and B‐B/F) are lost in the energy profile, being only revealed when particular information‐theoretical aspects of localizability (L or J), uniformity (D) and disorder (I) are considered. © 2012 Wiley Periodicals, Inc.