Yh. Chen et Lp. Hwang, Diffusion behavior of the benzene molecule in faujasite-type zeolite studied by double quantum filtered NMR, MAGN RES CH, 37, 1999, pp. S84-S92
Deuteron NMR relaxation methods including double quantum filtered (DQF) spe
ctral analyses were examined to study the dynamics of benzene molecules ads
orbed in faujasite-type zeolite. To describe the dynamics of benzene molecu
les, a modified cone model involving in-plane rotation, wobbling motion and
the characteristic order parameter was applied. The characteristic order p
arameter describes the intracage restricted reorientation for a single-site
adsorption. For multiple-site adsorption such as in NaY, the site-to-site
hopping processes result in cage disorder and yield a small characteristic
order parameter. The wobbling motion is induced by the diffusive motion and
therefore the correlation time of wobbling motion may be invoked to estima
te the self-diffusion coefficient of benzene adsorbed in NaY, DAY, USY and
NaX. Comparisons with kinetic Monte Carlo calculation, pulsed field gradien
t measurement, and other NMR relaxation studies are discussed. Copyright (C
) 1999 John Wiley & Sons, Ltd.