Theoretical Study of the Structural and Thermodynamic Properties of Amorphous SiO_(2) and Amorphous SiO_(2) with an Oxygen Defect Center

Structural properties and thermodynamic properties of amorphous SiO_(2)(a-SiO_(2)) and amorphous SiO_(2) with an oxygen defect ceuter (a-SiO_(2)-ODC) are investigated by using interatomic pair potentials.Amorphous configurations of SiO_(2) glass are constructed by quenching using the molecular-dynamics method and subsequent relaxation using the first-principles method.The numerical result demonstrates that the calculated short-range structural parameters coincide well with the previous experimental and theoretical results reported.The thermodynamic properties including specific heat,Debye temperature,vibrational entropy,and so on are analyzed by calculating the phonon density.Furthermore,mechanical properties of both structures are obtained.