Dynamics of a hydrogenated silica xerogel: A neutron scattering study

Neutron scattering measurements of a hydrogenated vitreous silica (or xerogel) sample reveal an unexpectedly high mean-square displacement of the silanol hydrogen atoms at 150 and 300 K. At 150 K, the spectrum mimics the boson peak of vitreous silica. The finding suggests a large local displacement of the boson peak modes at the breaking points of the continuous random network.