scholarly journals Communication: Paramagnetic NMR chemical shift in a spin state subject to zero-field splitting

2013 ◽  
Vol 138 (2) ◽  
pp. 021103 ◽  
Author(s):  
Alessandro Soncini ◽  
Willem Van den Heuvel
Keyword(s):  
Chemical Shift ◽  
Spin State ◽  
Paramagnetic Nmr ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Nmr Chemical Shift ◽  
Field Splitting

scholarly journals Modelling the Effect of Zero-Field Splitting on the 1H, 13C and 29Si Chemical Shifts of Lanthanide and Actinide Compounds

2019 ◽  
Vol 5 (1) ◽  
pp. 3
Author(s):  
Austin Lloyd ◽  
Helen Moylan ◽  
Joseph McDouall
Keyword(s):  
Chemical Shifts ◽  
Heavy Atom ◽  
Ground States ◽  
Paramagnetic Nmr ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Structural Characterisation ◽  
Chemical Systems

The prediction of paramagnetic NMR (pNMR) chemical shifts in molecules containing heavy atoms presents a significant challenge to computational quantum chemistry. The importance of meeting this challenge lies in the central role that NMR plays in the structural characterisation of chemical systems. Hence there is a need for reliable assignment and prediction of chemical shifts. In a previous study [Trends in Physical Chemistry, 17, 25–57, (2017)] we looked at the computation of pNMR chemical shifts in lanthanide and actinide complexes using a spin Hamiltonian approach. In that study we were principally concerned with molecules with S = 1/2 ground states. In the present work we extend that study by looking at the effect of zero field splitting (ZFS) for six complexes with S = 3/2 ground states. It is shown that the inclusion of ZFS can produce substantial shifts in the predicted chemical shifts. The computations presented are typically sufficient to enable assignment of experimental spectra. However for one case, in which the peaks are closely clustered, the inclusion of ZFS re-orders the chemical shifts making assignment quite difficult. We also observe, and echo, the previously reported importance of including the paramagnetic spin-orbit hyperfine interaction for 13 C and 29 Si atoms, when these are directly bound to a heavy element and thus subject to heavy-atom-light-atom effects. The necessary computations are very demanding, and more work is needed to find theoretical and computational approaches that simplify the evaluation of this term. We discuss the computation of each term required in the spin Hamiltonian. The systems we study in this work are restricted to a single heavy atom ion (one Nd(III) and five U(III) complexes), but typify some of the computational complexity encountered in lanthanide and actinide containing molecules.

Correlating the axial Zero Field Splitting with the slow magnetic relaxation in GdIII SIMs

2021 ◽  
Author(s):  
Júlia Mayans ◽  
Albert Escuer
Keyword(s):  
Magnetic Relaxation ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Slow Magnetic Relaxation

A possible relation between the value of the axial Zero Field Splitting and the occurrence of field-induced slow magnetic relaxation has been established for a new gadolinium(iii) compound.

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