NQR parameters: Electric field gradient tensor and asymmetry parameter studied in terms of density functional theory

Abstract

AbstractThe calculations of the electric field gradients were performed in the different basis sets at the selected ab initio, density functional theory (DFT), and ECP levels of the theory. The most reliable QCC and η values were obtained within the DFT and with the use of B3LYP functional and middle 6‐31G* or extended 6‐311G* basis sets. The universality of the B3LYP/6‐31G* method was checked by comparing the experimental and calculated Up values as only such a comparison enables assessment of the quality of the results obtained for different (heavy and light) nuclei. The NQR parameters obtained with the use of all‐electrons (AE) and pseudopotential (ECP) methods for a group of halogens or nitrogen‐containing compounds were compared and the former were found to be close to the experimental values. The explanation of so extremely small values of EFG calculated with the use of pseudopotential was proposed. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003