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Calculation of the diamagnetic component of the nuclear screening constant for C, N, O and F
Author(s) -
Ebraheem K. A. K.,
Webb G. A.,
Witanowski M.
Publication year - 1976
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270080610
Subject(s) - diamagnetism , atomic orbital , gauge (firearms) , constant (computer programming) , physics , component (thermodynamics) , molecular orbital , term (time) , expression (computer science) , gauge theory , atomic physics , variable (mathematics) , quantum mechanics , mathematical physics , chemistry , computational chemistry , molecular physics , molecule , mathematics , materials science , mathematical analysis , electron , computer science , magnetic field , metallurgy , programming language
‘Local’ and ‘nonlocal’ contributions to σ d are calculated by INDO molecular orbital methods. It is demonstrated, by means of Pople's approach 5 using ‘gauge dependent’ atomic orbitals, that σ local dis effectively constant for C, N, O or F in a number of chemically different environments and that σ nonlocal dis negligible. The use of Flygare's method 12 produces a significant and variable ‘nonlocal’ contribution, which renders σ d in this formulation comparable to the gauge dependent term in Ramsey's expression.