CHEMICALLY-INDUCED CHANGES IN THE MAGNETIC-MOMENTS IN TRANSITION-METAL MONOMERS AND DIMERS

Self-consistent molecular orbital calculations based on the generalize d gradient approximation to the density functional theory reveal that dinitrogen interacting with transition metal monomers and dimers can s ubstantially alter their underlying spin multiplicity. In particular, the coupling between spins of two Cr atoms in Cr-2 can change from ant i-ferromagnetic to ferromagnetic with the atomic moment almost intact even when N-2 is molecularly adsorbed. This effect, caused by the dila tion of the metal-metal bond, can have an important impact in the stud y of magnetism in general. (C) 1998 Elsevier Science B.V. All rights r eserved.