We use the dynamical mean-field theory to study a p-d Hubbard Hamiltonian for
LaCoO3 derived from ab initio calculations in local density approximation
(LDA+DMFT scheme). We address the origin of local moments observed above 100 K
and discuss their attribution to a particular atomic multiplet in the presence
of covalent Co-O bonding. We show that in solids such attribution, based on the
single ion picture, is in general not possible. We explain when and how the
single ion picture can be generalized to provide a useful approximation in
solids. Our results demonstrate that the apparent magnitude of the local moment
is not necessarily indicative of the underlying atomic multiplet. We conclude
that the local moment behavior in LaCoO3 arises from the high-spin state of Co
and explain the precise meaning of this statement
