Structure and magnetic ordering in Cr-8 and Cr-13 clusters

Theoretical studies of the equilibrium geometries, electronic: structure, a nd magnetic properties of Cr-8 and Cr-13 clusters have been carried out usi ng the local-spin-density approximation in the density-functional theory. S everal nearly degenerate isomers have been identified for both these cluste rs. In contrast to the recent studies of Cheng and Wang [Phys. Rev. Lett. 7 7, 51 (1996)], no indication of dimerization was found in the groundstate g eometry of Cr-8 The isomers have different magnetic properties. Among the t hree nearly degenerate isomers of Cr-8, two are antiferromagnetic while the other is ferromagnetic with a net moment of 4.0 mu(B). Cr-13, on the other hand, has two nearly degenerate isomers-a ferrimagnetic one with a net mom ent of 14.0 mu(B), and a ferromagnetic one with a net moment of 2.0 mu(B). These results are consistent with collision-induced dissociation and magnet ic deflection experiments. [S0163-1829(99)08147-3].