Validation and calibration of the embedded-cluster method was performed in order to study its applicability to modeling defects in amorphous silica, where defect models were not well established. The well-studied E4’ and E1’ centers in α-quartz were used as test systems, and the results were compared with experimental data and with the results of periodic density-functional theory calculations. The present method could reproduce the essential physics of both centers, in good agreement with experiment. The relative energies of different configurations obtained in the present calculations were consistent for the 2 centers and were in qualitative agreement with experiment. The calculated hyperfine parameters agreed with experimental values to within 20%. The defect-induced relaxation propagated for more than 10Å on the puckered side of the E1’ center. Factors were considered which governed the accuracy of calculations of relative defect energies in crystalline and amorphous silica.

Calibration of Embedded-Cluster Method for Defect Studies in Amorphous Silica. A.S.Mysovsky, P.V.Sushko, S.Mukhopadhyay, A.H.Edwards, A.L.Shluger: Physical Review B, 2004, 69[8], 085202 (10pp)