An ab initio study of C40, C40+, C40H4, Nb+@C40, Nb+C39 and Nb+@C40H4 clusters

The Becke-3–Lee–Yang–Parr (B3LYP) method was employed to study the equilibrium geometries and electronic structures of C40, C40H4, C36N4, C40+, Nb+@C40, Nb+C39 and Nb+@C40H4 clusters. The calculations indicated that the C40(Td) cage has an 5A2 open-shell ground state and behaves as a reactive hollow superatom with an effective valence of 4. C40H4(Td) and C36N4(Td) were proven to have an extraordinary thermodynamic stability with the 1A1 closed-shell ground state. Nb+C39 was calculated under the C3v symmetry; it resembles C40+(C3v) and shows more stability than Nb+@C40(Td). The similarity between the derivatives of C40 and those of C28 was also revealed.