Ab initio computations of zero-field splitting parameters and effective exchange integrals for single-molecule magnets (Mn 12 - and Mn 11 Cr-acetate clusters)

Polyhedron ◽  
2017 ◽  
Vol 136 ◽  
pp. 159-169 ◽  
Author(s):  
Shinsuke Sano ◽  
Takashi Kawakami ◽  
Shohei Yoshimura ◽  
Mitsuo Shoji ◽  
Shusuke Yamanaka ◽  
...  
Keyword(s):  
Ab Initio ◽  
Single Molecule ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Single Molecule Magnets ◽  
Field Splitting ◽  
Effective Exchange ◽  
Ab Initio Computations

scholarly journals Is [ReCl4(CN)2]2− a good Building Block for Single Molecule Magnets? A Theoretical Investigation.

2022 ◽  
Author(s):  
Christoph van Wüllen ◽  
Eva M. V. Kessler
Keyword(s):  
Single Molecule ◽  
Building Blocks ◽  
Ligand Field ◽  
Zero Field ◽  
Spin Orbit ◽  
Computational Results ◽  
Zero Field Splitting ◽  
Single Molecule Magnets ◽  
Field Splitting ◽  
Orbit Perturbation

Building blocks containing $5d$ spin centres are promising for constructing single molecule magnets due to their large spin-orbit interaction, but experimental and computational results obtained so far indicate that this might not be the case for Re$^\textrm{IV}$ centres in an octahedral environment. Density functional results obtained in this work for [ReCl$_4$(CN)$_2$]$^{2-}$ and trinuclear complexes formed by attaching Mn$^\textrm{II}$ centres to the cyano ligands indicate that zero field splitting in such complexes exhibits large rhombicity (which leads to fast relaxation of the magnetisation) even if there are only small distortions from an ideal geometry with a four-fold symmetry axis. This is already apparent if second-order spin-orbit perturbation theory is applied but even more pronounced if higher-order spin-orbit effects are included as well, as demonstrated by wavefunction based calculations. Computational results are cast into a ligand field model and these simulations show that especially a distortion which is not along the $C_4/C_2$ axeshas a large effect on the rhombicity. Quantum simulations on these complexes are difficult because the zero field splitting strongly depends on the energetic position of the low-lying doublets from the $t_{2g}^3$ configuration.

Ab initio calculation of the zero-field splitting parameters of vinylmethylene

1983 ◽  
Vol 87 (24) ◽  
pp. 4833-4839 ◽  
Author(s):  
David Feller ◽  
Weston Thatcher Borden ◽  
Ernest R. Davidson
Keyword(s):  
Ab Initio ◽  
Ab Initio Calculation ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting

An ab initio calculation of the zero‐field splitting parameters of the 3A′′ state of formaldehyde

1980 ◽  
Vol 73 (2) ◽  
pp. 865-869 ◽  
Author(s):  
Ernest R. Davidson ◽  
James C. Ellenbogen ◽  
Stephen R. Langhoff
Keyword(s):  
Ab Initio ◽  
Ab Initio Calculation ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting

scholarly journals Vibrational Coherences in Manganese Single-molecule Magnets after Ultrafast Photoexcitation

2018 ◽  
Author(s):  
Florian Liedy ◽  
Robbie McNab ◽  
Julien Eng ◽  
Ross Inglis ◽  
Thomas Penfold ◽  
...  
Keyword(s):  
Data Storage ◽  
Single Molecule ◽  
Optical Data Storage ◽  
Transient Absorption Spectroscopy ◽  
Optical Data ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Single Molecule Magnets ◽  
Teller Distortion ◽  
Jahn Teller

<p>Single-Molecule Magnets (SMMs) are metal complexes with two degenerate magnetic ground states arising from a non-zero spin ground state and a zero-field splitting. SMMs are promising for future applications in data storage, however, to date the ability to manipulate the spins using optical stimulus is lacking. Here, we have explored the ultrafast dynamics occurring after photoexcitation of two structurally related Mn(III)-based SMMs, whose magnetic anisotropy is closely related to the Jahn-Teller distortion, and demonstrate coherent modulation of the axial anisotropy on a femtosecond timescale. Ultrafast transient absorption spectroscopy in solution reveals oscillations superimposed on the decay traces with corresponding energies around 200 cm<sup>−1</sup>, coinciding with a vibrational mode along the Jahn-Teller axis. Our results provide a non-thermal, coherent mechanism to dynamically control the magnetisation in SMMs and open up new molecular design challenges to enhance the change in anisotropy in the excited state, which is essential for future ultrafast magneto-optical data storage devices.</p>

An ab initio MO study of heavy atom effects on the zero-field splitting tensors of high-spin nitrenes: how the spin–orbit contributions are affected

2014 ◽  
Vol 16 (19) ◽  
pp. 9171-9181 ◽  
Author(s):  
Kenji Sugisaki ◽  
Kazuo Toyota ◽  
Kazunobu Sato ◽  
Daisuke Shiomi ◽  
Masahiro Kitagawa ◽  
...  
Keyword(s):  
Ab Initio ◽  
High Spin ◽  
Heavy Atom ◽  
Zero Field ◽  
Spin Orbit ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Ab Initio Mo

The CASSCF and hybrid CASSCF–MRMP2 methods reproduce the ZFS tensors of spin-septet 2,4,6-trinitrenopyridines, focusing on the heavy atom effects on the spin–orbit terms of the tensors.

Ab initio and DFT studies of the spin–orbit and spin–spin contributions to the zero-field splitting tensors of triplet nitrenes with aryl scaffolds

2011 ◽  
Vol 13 (15) ◽  
pp. 6970 ◽  
Author(s):  
Kenji Sugisaki ◽  
Kazuo Toyota ◽  
Kazunobu Sato ◽  
Daisuke Shiomi ◽  
Masahiro Kitagawa ◽  
...  
Keyword(s):  
Ab Initio ◽  
Zero Field ◽  
Spin Orbit ◽  
Dft Studies ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Ab Initio And Dft

scholarly journals First-Principles Investigations of Magnetic Anisotropy and Spin-Crossover Behavior of Fe(III)-TBP Complexes

2020 ◽  
Author(s):  
Rishu Khurana ◽  
Sameer Gupta ◽  
Md. Ehesan Ali
Keyword(s):  
Single Molecule ◽  
First Principles ◽  
Density Functional ◽  
Spin Crossover ◽  
Zero Field ◽  
Spin States ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
B3lyp Functional ◽  
D Values

<div>With the ongoing efforts to obtain mononuclear 3d-transition metal complexes that manifest slow relaxation of magnetization and hence, can behave as single molecule magnets (SMMs), we have modelled 14 novel Fe(III) complexes out of which nine behave as potential SMMs. These complexes possess large zero-field splitting (ZFS)</div><div>parameter D in the range of -40 to -60 cm<sup>-1</sup>. The first-principles investigation of the ground-spin state applying density functional theory (DFT) and wave-function based</div><div>multi-configurations methods e.g. SA-CASSCF/NEVPT2 are found to be quite consistent except for few delicate cases with near degenerate spin-states. In such cases, the</div><div>hybrid B3LYP functional is found to be biased towards high-spin (HS) state. Altering the percentage of exact exchange admixed in B3LYP functional leads to intermediate spin</div><div>(IS) ground state consistent with the multireference calculations. The origin of large zero field splitting (ZFS) in the Fe(III)-based trigonal bipyramidal (TBP) complexes</div><div>is investigated and the D-values are further tuned by varying the axial ligands with group XV elements (N, P and As) and equatorial halide ligands from F, Cl, Br and I. Furthermore, a number of complexes are identified with very small Gibbs free energy values indicating the possible spin-crossover phenomenon between the bi-stable spin-states.</div>

Mixed valency in polynuclear Mn II /Mn III , Mn III /Mn IV and Mn II /Mn III /Mn IV clusters: a foundation for high-spin molecules and single-molecule magnets

2007 ◽  
Vol 366 (1862) ◽  
pp. 113-125 ◽  
Author(s):  
Theocharis C Stamatatos ◽  
George Christou
Keyword(s):  
Single Molecule ◽  
Exchange Interactions ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Single Molecule Magnets ◽  
Zero Field Splitting Parameter ◽  
Jahn Teller ◽  
Splitting Parameter ◽  
Molecular Spin ◽  
Molecular Compounds

Mixed-valent Mn/O dinuclear and polynuclear molecular compounds containing Mn III are almost without exception trapped valence. Large differences between the strengths of the exchange interactions within Mn II Mn III , Mn III Mn III and Mn III Mn IV pairs lead to situations where Mn III Mn IV interactions, the strongest of the three mentioned and antiferromagnetic in nature, dominate the intramolecular spin alignments in trinuclear and higher nuclearity mixed-valent complexes and often result in molecules that have large, and sometimes abnormally large, values of molecular spin ( S ). When coupled to a large molecular magnetoanisotropy of the easy-axis-type (negative zero-field splitting parameter, D ), also primarily resulting from individual Jahn–Teller distorted Mn III centres, such molecules will function as single-molecule magnets (molecular nanomagnets). Dissection of the structures and exchange interactions within a variety of mixed-valent Mn x cluster molecules with metal nuclearities of Mn 4 , Mn 12 and Mn 25 allows a ready rationalization of the observed S , D and overall magnetic properties in terms of competing antiferromagnetic exchange interactions within triangular subunits, resulting spin alignments and relative orientation of Mn III JT axes. Such an understanding has provided a stepping stone to the identification of a ‘magnetically soft’ Mn 25 cluster whose groundstate spin S value can be significantly altered by relatively minor structural perturbations. Such ‘spin tweaking’ has allowed this cluster to be obtained in three different forms with three different groundstate S values.

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