https://doi.org/10.1007/s100510170067
Finite-temperature characterization and simulations of the molecular assemblies Mn6 and Ni12
1
Computational Physics Division, Institute of Physics, A. Mickiewicz
University, ul. Umultowska 85, 61-614 Poznań, Poland
2
Institute of Technology, Pedagogical
University in Zielona Góra, Poland
3
Dipartimento di Scienze Fisiche,
Università di Napoli, Piazzale Tecchio, 80125 Napoli, Italy and INFM Unità di
Napoli, Italy
4
Dipartimento di Scienze Fisiche,
Università di Napoli, Complesso Universitario di Monte S. Angelo, 80125
Napoli, and INFM Unità di Napoli, Italy
5
Dipartimento di Chimica, Università di Firenze, via Maragliano 77, 50144
Firenze, Italy
Corresponding author: a filippo.esposito@na.infn.it
Received:
11
May
2001
Revised:
24
July
2001
Published online: 15 September 2001
Numerical transfer-matrix approach and exact diagonalization technique exploiting the point-group symmetry and the properties of the shift operator are worked out in the framework of quantum statistical mechanics for the isotropic Heisenberg spin Hamiltonian with the ring geometry. They are applied in large-scale simulations to the title high nuclearity cyclic clusters Mn6 (i.e. [ Mn(hfac)2NITPh] 6) and Ni12 (i.e. Ni12(O2CMe)12(chp)12(H2O)6(THF)6) in order to model quantitatively their magnetic properties. For Ni12 complex new experimental susceptibility data are also reported. New microscopic spin model parameters for both molecules are obtained from a fit of the theoretical susceptibility curves to the experimental results.
PACS: 75.10.Jm – Quantized spin models / 75.40.Cx – Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc. / 75.40.Mg – Numerical simulation studies / 75.50.Xx – Molecular magnets
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001