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The dual descriptor potential (DDP) has appeared in several papers, It is proposed as a local reactivity descriptor within the framework of the Conceptual Density Functional Theory and as a complementary tool of the molecular electrostatic potential (MEP) rather than the dual descriptor (DD). DDP provides information concerning the most energetically favorable sites to undergo nucleophilic and electrophilic attacks. Unlike the dual descriptor, DDP is directly related with energy. Furthermore, the DDP seems to depure the scalar field, allowing us to unveil the predominance of nucleophilic and electrophilic regions on a molecule. This is in stark contrast to the dual descriptor, which tends to scatter around the molecule, hindering the interpretation of the local reactivity on regions that exceed the atomic volume. To the best of our knowledge, this is the first time that DDP is represented as a 3D picture. To assess its capability to describe interaction among molecules, DDP was tested on some molecular systems, along with MEP. Results show that the joint use of these tools helps in the understanding of certain experimental evidences, serving as an alternative to the molecular orbital theory. [ABSTRACT FROM AUTHOR]

• We systematically analyzed the influence of diffuse functions on the dual descriptor. • Diffuse functions allows to use the frontier molecular orbital approximation confidently. • We evidenced the robustness of dual descriptor with ten basis sets. The finite difference approximation (FDA) allows us to compute dual descriptor correctly because it takes into account the relaxation effects that inner molecular orbitals experience. When these effects are irrelevant, we can use the frontier molecular orbital approximation (FMOA). Although FMOA omits relaxation effects and not FDA, both procedures should not yield too much different 3D representations of the dual descriptor. If so, the cause of such result lies in the fact that the respective basis set lacks diffuse functions, so artificially exacerbating the absence of relaxation effects aforementioned and yielding a remarkable inconsistency between FDA and FMOA. [ABSTRACT FROM AUTHOR]

By means of the conceptual density functional theory, the socalled dual descriptor (DD) has been adapted to be used in any closed-shell molecule that presents degeneracy in its frontier molecular orbitals. The latter is of paramount importance because a correct description of local reactivity will allow to predict the most favorable sites on a molecule to undergo nucleophilic or electrophilic attacks; on the contrary, an incomplete description of local reactivity might have serious consequences, particularly for those experimental chemists that have the need of getting an insight about reactivity of chemical reagents before using them in synthesis to obtain a new compound. In the present work, the old approach based only on electronic densities of frontier molecular orbitals is replaced by the most accurate procedure that implies the use of total electronic densities thus keeping consistency with the essential principle of the DFT in which the electronic density is the fundamental variable and not the molecular orbitals. As a result of the present work, the DD will be able to properly describe local reactivities only in terms of total electronic densities. To test the proposed operational formula, 12 very common molecules were selected as the original definition of the DD was not able to describe their local reactivities properly. The ethylene molecule was additionally used to test the capability of the proposed operational formula to reveal a correct local reactivity even in absence of degeneracy in frontier molecular orbitals. [ABSTRACT FROM AUTHOR]