Thermal Capacity of Vitreous Silica

It is assumed that the atoms in vitreous silica can be regarded as independent oscillators. Each silicon atom is taken as having three independent equal frequencies and each oxygen as having two equal transverse frequencies and one different longitudinal frequency. Reasonable values assigned to these frequencies give a calculated thermal‐capacity curve which is a fairly good approximation of the experimental curve except at very high and very low temperatures. These data also throw light on the reason for the very low thermal expansion of vitreous silica.