The solubility of argon in vitreous silica

A modified Seiverts method was used to measure inert gas solubility in fused silica. Using the original (average site) model equation, and a solubility site density of N s = 2.3 × 10 21/cm 3, helium solubility data gave a vibrational frequency for the helium atom of 4.6 × 10 12 s −1 and a binding energy of −2.02 kcal/mol. Using a vibrational frequency value of 1.5 × 10 12 s −1 for the argon atom, the argon solubility data gave a binding energy of −7.0 kcal/mol and a solubility site density of 9.8 × 10 19/cm 3. The density of accessible sites to argon atoms is reasonably consistent with a log-normal model of interstitial site structure.