Local structure analysis of γ-radiation-induced defects and Fe3+ impurities in soda-lime-silica: X-band EPR simulation

Abstract

This study measured and simulated continuous wave X-band electron paramagnetic resonance (cw-EPR) spectra of γ-irradiated (nuclear decay of ⁶⁰Co) at 300 K soda-lime-silicate (SLS) glass to analyze the effects on Fe³⁺ ions from Fe₂O₃ impurities. Three radiation-induced hole-center paramagnetic defects were identified, though simulating the broad electron-center signals was challenging. A prominent Fe³⁺ resonance line (g∼ 4.28) was simulated using a rhombic spin Hamiltonian, and γ-irradiation caused a shift in the Fe³⁺ g_isovalue. While the axial zero-field-splitting (ZFS) parameter (D) remained stable, the rhombic ZFS parameter (E) decreased with increasing radiation, increasing rhombicity (λ= |E/D|). This suggests that radiation-induced defects distort the Fe³⁺ sites' electronic environment in the glass network. In summary, the study reveals the local structural evolution of radiation-induced defects in SLS glass and the local structure of Fe³⁺ impurities under γ-irradiation.