Fabien Jousse, Daniel P. Vercauteren and Scott M. Auerbach,
``How Does Benzene in Na-Y Couple to Zeolite Framework Vibrations,''
J. Phys. Chem. B 104, 8768-8778 (2000).
Abstract
Constrained energy minimization, equilibrium and nonequilibrium molecular dynamics calculations, and constrained Monte
Carlo simulations were used to determine the influence of the coupling between benzene adsorbed in a NaY zeolite model
(Si/Al = 2) and the framework vibrations on benzene site-to-site dynamics. Benzene at an SII site is strongly coupled to the
nearby Na(II) cation, resulting in a decrease of the external vibrational frequency of the center-of-mass of benzene away
from this cation by 60 cm-1. Despite this coupling, framework vibrations have remarkably little influence on the site-to-site
rate constants of benzene. Although with a fixed framework no dissipation of the excess kinetic energy of the adsorbed
molecule can take place and thus no thermalization to equilibrium, energy redistribution from the translational motion of
benzene into the internal degrees of freedom of the flexible molecule is seen to provide a good thermalization.
Prof SM Auerbach
10 January 2003