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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 4, Number 3
BKCSDE 4(3)
March 20, 1983 

 
Title
Calculation of NMR Shift in Paramagnetic System When the Threefold Axis is Chosen as the Quantization Axis (Ⅰ). The NMR Shift for a 3d1 System in a Strong Crystal Field of Octahedral Symmetry
Author
Sangwoon Ahn, Euisuh Park, Kee Hag Lee
Keywords
Abstract
The NMR shift arising from the electron angular momentum and the electron spin dipolar-nuclear spin angular momentum interaction has been examined for a 3d1 system in a strong octahedral crystal field when the threefold axis is chosen as the quantization axis. To investigate the NMR shift in this situation, first, we have extended the evaluation of the hyperfine integrals to any pairs of 3d orbitals adopting a general method which is applicable to a general vector R, pointing in arbitrary direction in space. Secondly, a general expression using a nonmultipole technique is derived for the NMR shift resulting from the electron angular momentum and the electron spin dipolar-nuclear spin angular momentum interactions. From this expression all the multipolar terms are determined. ΔB/B for the 3d1 system in this case is compared with that for the 3d1 system when the z axis is chosen as the quantization axis. When we choose the threefold axis as the quantization axis, it is found that along the , and axes, ΔB/B values are significantly different from each other and along the , <-1-1-1>, <-11-1>, , <-1-11>, , and <-111> axes, ΔB/B values are however the same. We also find that the 1/R7 term contributes dominantly to the NMR shift for all values of R. When 1/R5 term is included, there is good agreement between the exact solution and the multipolar terms when R ≤ 0.35 nm.
Page
103 - 114
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