Anisotropie reorientation dynamics of benzene molecules adsorbed on graphite, alumina, and zeolite Y

Abstract

Frequency-resolved deuteron spin-lattice relaxation times of benzene adsorbed at monolayer coverage on graphitized carbon black and on η-alumina as well as at full loading in the voids of zeolite NaY were measured at temperatures in the range 250-77 K. The results obtained can be explained by the hexad axis reorientation of the molecules with the following correlation times τ c/ps: 0.1 exp(7.9 kJ mol −1 RT ) (graphite); 0.1 exp(7.4 kJ mol −1 RT ) (η-alumina); 1.5 exp(4.9 kJ mol −1 RT ) (NaY) . These results are compared with the correlation times for bulk crystalline benzene and are discussed in the context of recent molecular dynamics simulations.