Calculation of Exchange Coupling Constants in Mn-Ce Molecular Magnets
Dian-Teng Chen1 , Xiang-Guo Li1 , Yun-Peng Wang1 , Sayak Das Gupta2 , Xiao-Guang Zhang1 , George Christou2 , Hai-Ping Cheng1
1 Department of Physics and Quantum Theory Project, University of Florida, Gainesville, Florida 32611, USA
2 Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA
Recently several Mn-Ce molecular magnets have been synthesized, including Mn3Ce2 and Mn5Ce3 with three different ligands, but their magnetic properties are yet to be detailed. We calculate the energies of all the spin configurations of each of these molecules by density functional theory. From the calculations of each molecule, we determine a Heisenberg Hamiltonian with antiferromagnetic or ferromagnetic exchange coupling constants using both spin-projected and non-spin-projected energies of the broken symmetry solutions and compare the results to the coupling constants fitted from experimental susceptibility data.