Energy decomposition analysis of F-M bonds in F2M (M=O, S, Se) compounds

The energy decomposition analysis (EDA) is a powerful method for a quantitative interpretation of chemical bonds in terms of four major expressions. The instantaneous interaction energy ΔEint between two fragments A and B in a molecule A–B is partitioned in four terms, namely, (1) the quasi-classical electrostatic interaction ΔEelstat between the fragments, (2) the repulsive exchange (Pauli) interaction ΔEPauli between electrons of the two fragments having same spin, (3) the orbital interaction ΔEorb, which comes from the orbital relaxation and the orbital mixing between the fragments and (4) dispersion energy.In this work, the nature of F-M bonds in F2M (M=O, S, Se) compounds have been investigated at BP86-D3/TZ2P//M06/def2−TZVPP level of theory with C2v symmetry constraints by using the program package ADF2013.01. The calculated values for the orbital interactions ΔEorb can be used as an indicator for the best description of the F-M interactions. Those EDA calculations which give the smallest ΔEorb value indicate which fragments are the best choices for describing the bonding situation, because the least alteration of the electronic charge distribution is required to yield the electronic structure of the molecule [1]. The data in Table 1 illustrate that fragmentation of (c) gives the smallest ΔEorb value for F2O, F2S and F2Se. The latter fragments show that the (F)2 has has s2 pσ1 pπ┴2 pπǁ2 orbital occupations and O, S and Se atoms have s2 pσ1 pπ┴1 pπǁ2 orbital occupations (See Table 1).