Update 2 of: Electrophilicity Index

An analysis of philicity provides the local information of a particular atomic site in a molecule being prone to elctrophilic, nucleophilic, or radical attack. The various electrophilicity descriptors reported in this section may be broadly classified into three categories: the kinetic descriptor that measures the rate at which an electrophilic attack takes place, the thermodynamic descriptor which measures the ease of such an attack, and a combination of these two approaches through a linear free energy relationship. The majority of the empirical electrophilicity scales introduced so far are global in nature. Their local variants were developed only recently, and most of them are based on the Fukui function. The concept of confined quantum mechanical systems stems from the idea of simulating the effect of pressure on atoms or molecules by confining them in impenetrable spherical boxes.