Related Experiment Video
Updated: Nov 9, 2025
07:42
Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains
Published on: July 20, 2022
3.0K
Magnetic Anisotropy in a Cubane-like Ni4 Complex: An Ab Initio Perspective
1SUBATECH, UMR CNRS 6457, IN2P3/IMT Atlantique/Université de Nantes, 4 rue A. Kastler, 44307 Nantes Cedex 3, France.
Inorganic Chemistry
|April 16, 2021
Summary
This study computes zero-field splitting (ZFS) in a tetranickel(II) complex using advanced quantum methods. Results reveal weak ferromagnetic couplings and challenge the use of single crystallographic structures for magnetic anisotropy calculations.
Area of Science:
- Quantum Chemistry
- Magnetochemistry
- Computational Materials Science
Background:
- Magnetic anisotropy arises from energy level degeneracy, typically modeled by spin Hamiltonians and zero-field splitting (ZFS).
- While ab initio studies are common for mononuclear complexes, research on polynuclear complexes is limited.
- Understanding ZFS is crucial for designing molecular magnets with specific magnetic behaviors.
Purpose of the Study:
- To compute the zero-field splitting (ZFS) of the ground S = 4 state in a tetranickel(II) complex using advanced multiconfigurational wave function theory.
- To investigate the magnetic coupling and anisotropy of the complex and assess the influence of single-site anisotropies.
- To evaluate the feasibility of including local orbital excited states for a manageable ZFS treatment and compare computational results with experimental data.
Main Methods:
- Application of advanced multiconfigurational wave function theory methods.
- Computation of isotropic magnetic couplings using ab initio quantum mechanical calculations.
- Calculation of single-site magnetic anisotropies and ZFS for the full tetranickel(II) complex.
Main Results:
- Confirmed weak ferromagnetic couplings between nickel(II) centers in the tetranickel(II) complex.
- Demonstrated that single-site anisotropy axes are not optimally oriented for significant uniaxial molecular anisotropy.
- Revealed that low-lying orbitally excited S = 3 states significantly contribute to the ZFS, alongside weak uniaxial anisotropy in the S = 4 state.
Conclusions:
- The study provides accurate ZFS parameters for the tetranickel(II) complex, offering insights into its magnetic behavior.
- The findings suggest that simplified computational approaches involving only a few local orbital excited states can provide consistent ZFS treatments.
- Results question the common practice of relying solely on a single crystallographic structure for computing magnetic anisotropy parameters, advocating for more comprehensive structural considerations.
More Related Videos
09:06Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
Published on: March 24, 2019
8.3K
08:55Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
8.7K
Related Concept Videos
02:42Valence Bond Theory
10.0K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
10.0K
03:02Colors and Magnetism
12.7K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.7K
00:59Atomic Nuclei: Nuclear Magnetic Moment
2.5K
All atomic nuclei are positively charged. When they have a nonzero spin, they behave like rotating charges. As a consequence of their charge and spin, these nuclei generate a magnetic field (B). This, in turn, gives rise to a magnetic moment (μ), which is randomly oriented in the absence of an external magnetic field. When an external magnetic field (B0) is applied, the magnetic moment vectors can align with the field or against it in 2 + 1 orientations. A hydrogen nucleus, which is just a...
2.5K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
45.8K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
45.8K
02:58Crystal Field Theory - Octahedral Complexes
28.7K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
28.7K
01:03Atomic Nuclei: Nuclear Spin State Overview
1.4K
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
1.4K