Magnetostructural Dependencies in 3d²Systems: The Trigonal Bipyramidal V³⁺Complex

Abstract

We introduce a multiconfigurational approach to study the magnetostructural correlations in 3d2 systems. The theoretical framework represents a restricted active space self‐consistent field method, with active space optimized to the number of all non‐bonding orbitals. To demonstrate the validity and effectiveness of the method, we explore the physical properties of the trigonal bipyramidal spin‐one single‐ion magnet (normalC6F5)3trenVCNtBu. The obtained theoretical results show good agreement with the experimental data available in the literature. This includes measurements for the magnetization, low‐field susceptibility, continuous wave electron paramagnetic resonance, and photoluminescence spectroscopy. The proposed method may be reliably applied to a variety of 3d2 magnetic systems. To this end, and for the sake completeness, we provide detailed analytical and numerical representations for the generic Hamiltonian's effective matrix elements related to the crystal field, exchange, spin–orbit, and Zeeman interactions.

Magnetic Behavior of Trigonal (Bi-)pyramidal 3d8 Mononuclear Nanomagnets: The Case of [Ni(MDABCO)2Cl3]ClO4

“…Here, l̂ i and ŝ i are the i-th electron’s orbital and spin operators, respectively. The series expansion of Coulomb and CF potentials is discussed in ref ( 45 ). Note that the effect of all orbital and spin magnetic dipole–dipole interactions into FSG is found to be negligible and hence are omitted from eq 1 .…”

“…The uniqueness is determined by all constraints that confine the electron orbital dynamics, preserving all relevant observables invariant. To this end, we make use of the exact diagonalization technique developed in ref ( 45 ) to characterize 3d 2 systems and later extended to explore the properties of 3d 8 -based 25 mononuclear nanomagnets. This very approach will be used to explore the unusual magnetic behavior of the compound [Ni(MDABCO) 2 Cl 3 ]ClO 4 , 37 exhibiting slightly distorted trigonal bipyramidal coordination.…”

Single-Ion Magnets with Giant Magnetic Anisotropy and Zero-Field Splitting

“…An important step forward in molecular nanomagnets’ comprehensive theoretical characterization is the use of well-established methods within their self-consistent framework: for example, the perturbation method 22 , 29 incorporating the residual electronic repulsion approach that ensures the conventional irreducible representation of orbital states and the complete active space variational one 30 (see also ref ( 29b )) based on the direct diagonalization technique. The accurate use of these methods will reduce the number of possible computational errors to the minimum.…”

A Self-Consistent Exact Diagonalization Approach to the Ground State Magnetic Properties of the Meridional [V(ddpd)2]3+ Complex

“…As one of the first three members in the first row of transition metals with less than a half-filled 3d subshell, the vanadium ion stands as a prospective candidate for the design of cheap, chemically stable, high-spin paramagnetic luminophore single-ion magnets [22,23] with the potential to pave the road to the application of all optically addressable molecular nanomagnets as units of future semiclassical information devices. The property of vanadium cations of having less than four active 3d electrons, however, classifies the associated coordination complexes, which are usually synthesized in a hexacoordinated [24][25][26][27][28] or pentacoordinated [29][30][31] crystal field (CF) as mononuclear nanomagnets with small zero-field splitting (ZFS) and negligible orbital unquenching at the ground state. Accordingly, this poses an inconvenience for the realization of efficient high-temperature optical control of the magnetization dynamics within the relevant band of spin multiplet transitions.…”

“…Furthermore, its focus is to provide a complete representation of the underlying electrons' correlations and reveal the genuine contribution of SO to the FS under the exhibited distortion. To this end, we carry out multiconfigurational, self-consistent quantum computations over the active electrons from the considered system by the method of exact diagonalization [30,41]. We calculate the total energy spectra, the corresponding ZFS, and the evolution of FSG under the action of the externally applied magnetic field.…”