First principle study of CrF n (n=1-7) nano clusters: An investigation of superhalogen properties

Quantum chemical calculations using gradient corrected density functional theory at B3LYP level reveals the unusual properties of a chromium (Cr) atom interacting with fluorine (F) atoms. Up to seven F atoms are bound to a single Cr atom, which results in increase of electron affinities as successive fluorine atoms are attached, reaching a peak value of 7.14 eV for CrF6. The large HOMO-LUMO energy gap, both in neutral and anionic form, further provide evidence of their stability. These unusual properties brought about by involvement of inner shell 3d-electrons, which not only allow CrF (n) (n = 1-7) clusters to belong to the class of superhalogens but also show that its valence can exceed the nominal value of 2.