INERT-GAS SOLIDS WITH NANOSCALE POROSITY

The structure and thermal properties of novel mesoporous inert-gas sol ids were studied by synchrotron x-ray diffraction. The materials were prepared by injecting a jet of helium containing dilute amounts of ine rt atoms and molecules (Ne, Kr, N-2) into superfluid helium. The chara cteristic size of the constituent building blocks is similar to 60 Ang strom, and the density is greater than or equal to 10(20) impurity ato ms per cm(3). The Kr and N-2 solids are stable outside of liquid He, u p to temperatures above 10 K. These materials may find various applica tions as a new type of porous medium for fundamental physics, as well as in cluster physics, matrix isolation spectroscopy, and catalysis of low temperature chemical reactions.