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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 28, Number 11
BKCSDE 28(11)
November 20, 2007 

 
Title
Simulation of 27Al MQMAS NMR Spectra of Mordenites Using Point Charge Model with First Layer Only and Multiple Layers of Atoms
Author
Seen Ae Chae, Oc Hee Han*, Sang Yeon Lee
Keywords
27Al MQMAS, Solid-state NMR, Mordenite, Point charge model, Si/Al ratio
Abstract
The 27Al multiple quantum magic angle spinning (MQMAS) nuclear magnetic resonance (NMR) spectra of mordenite zeolites were simulated using the point charge model (PCM). The spectra simulated by the PCM considering nearest neighbor atoms only (PCM-n) or including atoms up to the 3rd layer (PCM-m) were not different from those generated by the Hartree-Fock (HF) molecular orbital calculation method. In contrast to the HF and density functional theory methods, the PCM method is simple and convenient to use and does not require sophisticated and expensive computer programs along with specialists to run them. Thus, our results indicate that the spectral simulation of the 27Al MQMAS NMR spectra obtained with the PCM-n is useful, despite its simplicity, especially for porous samples like zeolites with large unit cells and a high volume density of pores. However, it should be pointed out that this conclusion might apply only for the atomic sites with small quadrupole coupling constants.
Page
2069 - 2074
Full Text
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