The structure of solid in porous Vycor glass

The structure of solid confined in porous Vycor glass has been studied as a function of temperature via x-ray diffraction. The confined solid has the same structure as the bulk solid but with a slightly larger lattice constant of 5.644 Å at 150 K compared to the bulk lattice constant of 5.624 Å at the same temperature. Broad diffraction peaks are observed indicating that the solid phase of the in the pores forms in small crystallites approximately 160 Å in diameter. This is comparable to the pore dimensions in the Vycor indicating that solidification occurs separately in each of the pores. A large temperature-independent static disorder, analogous to the Debye - Waller factor, was observed in the form of strong damping of the Bragg peaks with increasing Q.