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Calculation of NMR chemical shifts for taxol and α‐pinene within the generalized gradient approximation
Author(s) -
Bouř Petr
Publication year - 2002
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10386
Subject(s) - formalism (music) , chemical shift , basis set , chemistry , electromagnetic shielding , quantum chemical , hybrid functional , atomic orbital , computational chemistry , gauge (firearms) , invariant (physics) , density functional theory , statistical physics , molecule , computational physics , physics , quantum mechanics , materials science , art , musical , metallurgy , visual arts , electron
Simulations of the nuclear magnetic shielding within the generalized gradient approximation (GGA) for α‐pinene and taxol were carried out to assess the performance of the method for bigger molecules. The localized orbital/local origin gauge (LORG) formalism and the modified “0.05” Becke's three‐parameter exchange functional and the gradient‐corrected functional of Lee, Yang, and Paar (B3LYP) proposed recently by Wilson and others was used. A modest dependence of the results on the basis set size was observed. For the current implementation, the uncoupled calculations were up to 47 times faster than the usual coupled‐perturbed (CP)–gauge‐invariant atomic orbital (GIAO) method and provided similar accuracy. Reproducing both the absolute as the relative chemical shifts the GGA/LORG procedure can thus be used as a faster alternative to the coupled techniques. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003