Local structures of amorphous and crystalline phases of silica, SiO2, by neutron total scattering

We quantify the relationship between the atomic structures of the amorphous and the ordered and disordered crystalline phases of silica using neutron total scattering measurements to determine the local atomic configurations. The instantaneous local atomic arrangements of HP-tridymite and beta-crist obalite, both dynamically-disordered high-temperature crystalline phases, b ear a striking resemblance to the quenched structure of amorphous silica, u nlike those of the two phases of quartz and ordered alpha-cristobalite. The high-temperature phases are not domain averages of their respective low-te mperature phases. Our approach has wider application for characterization o f disordered crystalline structures in general.