Estimation of the zero-field splitting parameter, D, for polycrystalline samples of manganese (II) species in axial crystal fields

1970 ◽  
Vol 2 (1) ◽  
pp. 42-46 ◽  
Author(s):  
R.D Dowsing
2016 ◽  
Vol 52 (4) ◽  
pp. 753-756 ◽  
Author(s):  
Mamon Dey ◽  
Snigdha Dutta ◽  
Bipul Sarma ◽  
Ramesh Ch. Deka ◽  
Nayanmoni Gogoi

Subtle modulation of the coordination environment in seven coordinate Co(ii) complexes leads to a remarkable deviation in the axial zero field splitting parameter (D) in a predictable fashion.


Author(s):  
Rajeev Ranjan ◽  
Navneet Sinha ◽  
Sahdeo Kumar ◽  
Chandra Mauleshwar Chandra ◽  
Shivadhar Sharma

<em>Some complexes of Ni(II) have been prepared with 2-thio-3-acetyl hydantoin (TAHN) and 2-formyl pyridine thiosemicarbazone (FPTS). On the basis of elemental analysis and molar conductivity, the complexes have been formulated as NiL<sub>2</sub>X<sub>2</sub>, where L = TAHN or FPTS and X = Cl<sup>–</sup>, Br<sup>–</sup>, NCS<sup>–</sup>, ClO<sub>4</sub><sup>–</sup>. The infrared spectra of complexes and free ligand reveal that the ligand TAHN is co-ordinated through sulphur and acetyl oxygen, while FPTS ligand co-ordinates through heterocyclic nitrogen and sulphur to Ni(II) metal ion. The magnetic moment of these complexes are found to be 3.20-3.25 B.M. The values are greater than value (2.828 B.M) corresponding to two unpaired electrons of a d<sup>8</sup>-system. The appearance of four absorption bands in their electronic spectra reveal, the tetragonal distortion in the octahedral symmetry of complexes. The zero field splitting parameter(D) and the other crystal field parameters like Dq<sub>(xy)</sub>, Dq<sub>(z)</sub>, Dt have been calculated. The results show that, the tetragonal distortion parameter (Dt) increases in the order of NCS<sup>– </sup>&lt; Cl<sup>–</sup> &lt; Br<sup>–</sup> while the zero field splitting parameter (D) also increases in the same order for both the planer ligands.</em>


2006 ◽  
Vol 20 (30) ◽  
pp. 1917-1922 ◽  
Author(s):  
VIMAL KUMAR JAIN

The Newman superposition model has been applied to second-order zero-field splitting parameter [Formula: see text] taken from the literature for Mn2+in Hg(ClO4)2· 6 H2O , M ″ SiF6·6 H2O (M ″= Fe, Co, Zn ) and M ″ NbOF5·6 H2O (M ″= Co, Zn ). In the calculations, the local lattice relaxation has been taken into account. It is shown that nearly the same value of intrinsic parameter b2=-0.057(8) cm-1is obtained.


2021 ◽  
Vol 50 (10) ◽  
pp. 3468-3472
Author(s):  
Roman Boča ◽  
Ján Titiš ◽  
Cyril Rajnák ◽  
J. Krzystek

Magnetochemical standard HgCo(NCS)4 with positive zero-field splitting parameter D displays a slow magnetic relaxation strongly dependent upon the external magnetic field.


1995 ◽  
Vol 73 (11) ◽  
pp. 1869-1874 ◽  
Author(s):  
Olivier Parisel ◽  
Gaston Berthier ◽  
Eva Migirdicyan

Quantum mechanical calculations using ab initio and semi-empirical methods have been carried out for elucidating the electronic structure and geometry of 2-naphthylphenylcarbene conformers. The Z/cis conformer has the lowest ground state triplet energy, the lowest triplet–triplet (T0–T1) transition energy, as well as the largest zero-field splitting parameter D. A clear-cut relationship between the D value and the geometry is pointed out. Keywords: carbenes, conformational isomerism, triplet–triplet transitions, CS-INDO/CI calculations, ZFS D parameters.


2003 ◽  
Vol 68 (12) ◽  
pp. 2335-2343 ◽  
Author(s):  
Zdeněk Havlas ◽  
Mojmír Kývala ◽  
Josef Michl

The spin dipole-spin dipole and spin-orbit coupling contributions to the zero-field splitting parameter D of CH3-N, CH3-P, CH3-As, SiH3-N, SiH3-P, and SiH3-As have been calculated from CAS(12,11)/cc-pVTZ wave functions and the Breit-Pauli Hamiltonian at T1 B3LYP/cc-pVTZ optimized geometries. The spin-orbit coupling contributions represent a minor correction for the nitrenes, and bring the value computed for methylnitrene from 1.66 to 1.84 cm-1, in good agreement with experiment (1.72 cm-1). They dominate the spin-spin terms by an order of magnitude in phosphinidenes and by more than two orders of magnitude for arsinidenes. The properties of all these perfect axial biradicals follow expectations based on the simple algebraic 2-in-2 model of biradical structure.


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