Energy‐level diagrams of high‐spin and low‐spin molecules

Abstract

The magnetic energy-level diagrams for models of the Mn 12 and V 15 molecule are calculated using the Lanczos method with full orthogonalization and a Chebyshev-polynomial-based projector method. The effects of the Dzyaloshinskii-Moriya interaction on the appearance of energy-level repulsions and its relevance to the observation of steps in the time-dependent magnetization data are studied.

Single‐Molecule Magnets Under Pressure

“…[24][25][26][27] In addition, the energetic positions and nature of the next higher spin states and their possible impact on the low-temperature magnetic properties have been more a matter of speculation, rather than being based on unambiguous experimental evidence. In a recent study, [12] we addressed these points both experimentally and computationally, taking into account the four most important exchange interactions J 1 , J 2 , J 3 , and J 4 in the dodeca-nuclear molecule (see Fig.…”

“…Numerous attempts to determine the exchange parameters in Mn 12 -acetate are found in the literature. [24][25][26][27][29][30][31][32] A determination of the complete energy spectrum from a diagonalization of the full energy matrix with dimension 10 8 is out of the question, but sparse-matrix techniques allow the numerical calculation of the lowest-lying energy levels. On the basis of magnetostructural correlations in smaller exchange-coupled Mn 3+ -Mn 4+ complexes, both J 1 and J 2 (see Fig.…”

Temperature Dependence of ESR Intensity for the Nanoscale Molecular Magnet V15

“…4(b). Thus, the combination of the DCEM and the SIM provides a powerful method to elucidate the ESR of large molecular magnets such as V 15 .…”

“…7) However, the detail of the mechanism of this broad change is not fully understood yet. 15,16) One possible way to determine the mechanism of adiabatic change in V 15 is that we compare the numerically obtained ESR absorption curve of V 15 with the experimentally obtained one. With this motivation, in this paper, we establish numerical methods to study the ESR absorption curve obtained from the model Hamiltonian of V 15 .…”

“…19) However, this direct method is impossible in most cases because the dimension of the Hilbert space is quite large. For example, it is 2 15 = 32768 for V 15 . In this paper, we study the ESR absorption curve of V 15 by proposing two methods: one is the double Chebyshev expansion method (DCEM) and the other is the subspace iteration method (SIM).…”