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Theory of Magnetic Susceptibilities and NMR Chemical Shifts in Terms of Localized Quantities
Author(s) -
Kutzelnigg W.
Publication year - 1980
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.198000020
Subject(s) - diamagnetism , chemistry , paramagnetism , spurious relationship , chemical shift , coupling (piping) , coupling constant , inductive coupling , gauge (firearms) , condensed matter physics , computational chemistry , quantum mechanics , physics , magnetic field , statistics , mechanical engineering , mathematics , archaeology , engineering , history
A coupled Hartree–Fock theory for diamagnetic susceptibilities χ and chemical shifts σ in terms of localized MO's and individual gauge origins for the different MO's is derived. The new coupled Hartree–Fock equations and expressions for χ and σ differ from the traditional ones by the presence of “exchange coupling terms” (ECT) and “resonance coupling terms” (RCT). For the ECT, that are expected to be very small, a simple approximation is proposed. Both the ECT and the RCT can be decomposed into “diamagnetic” and “paramagnetic” contributions. Spurious paramagnetic terms due to inappropriate choices of the gauge origin are avoided in the present scheme. The possibility to include correlation effects is discussed.