MOLECULAR-TRANSPORT IN SUBNANOMETER PORES - ZERO-POINT ENERGY, REDUCED DIMENSIONALITY AND QUANTUM SIEVING

In microporous materials quantum effects in molecular adsorption and t ransport become of importance if the difference between pore diameter and the molecular hard core is no longer large compared to the de Brog lie wavelength of radial motion. Two aspects are discussed: the freezi ng of the radial degrees of freedom resulting in a one dimensional gas and the situation where the zero-point energy overcompensates the att raction of the walls, creating an energy barrier at the entrance of th e pores. In both cases the material can act as a quantum molecular sie ve.