Investigation of superhalogen properties of RhFn (n = 1–7) clusters using quantum chemical method

In this paper we have studied the interaction of Rhodium (Rh) atom with Fluorine (F) using density functional theory. Up to seven F atoms are bound to a single Rh atom which results in increase of electron affinities of the given molecule successively, reaching a peak value of 9.05 eV for RhF7. By using HOMO–LUMO gap, molecular orbital analysis, binding energy of these clusters, we examined its stability and reactivity. It is found that energy required for dissociation of F2 molecules are higher than energy required for dissociation of F atoms. The unusual properties are brought about by involvement of inner shell 4d-electrons, which not only allow RhFn clusters to belong to the class of superhalogens but also show that its valence can exceed the nominal value of 1.

Graphical abstractGraphical abstract shows a graph between electron affinity (EA) and number of Fluorine atoms. EA rises from 1.5 eV to 9.0 eV as the number of Fluorine atoms increases from 1 to 7. The EA of RhF7 (9.0 eV) is much higher than Cl atom, which has highest EA among all elements in the periodic table. Hence, we can conclude that RhFn (n ≥ 2) clusters may be considered to be superhalogens.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Present study points to the fact that RhFn (n = 1–7) belong to the class of superhalogens. ► RhFn clusters are found to be stable in the gas phase against dissociation to F and F2. ► The binding energy of NaRhF4 is found larger than that of NaF.