@article{ISI:000259690400057,
 abstract = {We present a theoretical approach to calculate the molecular magnetic
anisotropy parameters, D-M and E-M for single molecule magnets in any
eigenstate of the exchange Hamiltonian, treating the anisotropy
Hamiltonian as a perturbation. Neglecting intersite dipolar
interactions, we calculate molecular magnetic anisotropy in a given
total spin state from the known single-ion anisotropies of the
transition metal centers. The method is applied to Mn12Ac and Fe-8 in
their ground and first few excited eigenstates, as an illustration. We
have also studied the effect of orientation of local anisotropies on the
molecular anisotropy in various eigenstates of the exchange Hamiltonian.
We find that, in case of Mn12Ac, the molecular anisotropy depends
strongly on the orientation of the local anisotropies and the spin of
the state. The D-M value of Mn12Ac is almost independent of the
orientation of the local anisotropy of the core Mn(IV) ions. In the case
of Fe-8, the dependence of molecular anisotropy on the spin of the state
in question is weaker. We have also calculated the anisotropy constants
for several sets of exchange parameters and found that in Mn12Ac the
anisotropy increases with spin excitation gap, while in Fe-8, the
anisotropy is almost independent of the gap.},
 article-number = {104408},
 author = {Raghunathan, Rajamani and Ramasesha, S. and Sen, Diptiman},
 doi = {10.1103/PhysRevB.78.104408},
 eissn = {2469-9969},
 issn = {2469-9950},
 journal = {PHYSICAL REVIEW B},
 month = {SEP},
 number = {10},
 times-cited = {5},
 title = {Theoretical approach for computing magnetic anisotropy in single
molecule magnets},
 unique-id = {ISI:000259690400057},
 volume = {78},
 year = {2008}
}