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INDO/S parameterized calculations of some 13C nuclear screening data

✍ Scribed by M. Jallali-Heravi; G. A. Webb

Publisher: John Wiley and Sons
Year: 1978
Tongue: English
Weight: 309 KB
Volume: 11
Category: Article
ISSN: 0749-1581
DOI: 10.1002/mrc.1270111011

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✦ Synopsis

Abstract

Nuclear screening tensors, their anisotropies and ^13^C chemical shifts are calculated for a number of carbon environments and compared with the corresponding experimental data. The agreement found with the experimental results is an improvement over that obtained from CNDO/S parameterized calculations. The improvement stems from the inclusion of the one‐centre exchange integrals, which results in smaller values for the excitation energies from the INDO/S calculations. It is demonstrated that a linear relationship between ^13^C chemical shift and the lowest energy transition is not to be expected. The average values of the excitation energies of the various transitions contributing to the ^13^C screening are found to have significant variations.

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