ATOMIC AND ELECTRONIC-STRUCTURE AND CHEMICAL-REACTIVITY OF METAL-CLUSTERS

Platinum clusters were introduced into the crystals of a Y-zeolite, a porous silicoaluminate containing internal cavities called supercages with a diameter of 1. 3 nm. Two kinds of samples were prepared by finishing their preparation at a low (490 K) or high (673 K) temperature. The corresponding clusters are denoted as L and H respectively. It was determined by transmission electron microscopy (TEM) that the L clusters contain 20 atoms on the average. This critical finding by TEM led to a new interpretation of results obtained by means of a technique developed recently by the Fraissard group and based on to a new interpretation of results obtained by means of a technique developed recently by the Fraissard group and based on **1**2**9Xe NMR.