Magnetic resonance study of arsenic bonding sites in ternary chalcogenide glasses

⁷⁵As NQR and high-field NMR experiments have been performed on Ge_xAs_ySe_1−x−y glasses. Evolution of As bonding structure from arsenic sites with axially symmetric distribution of the electric field gradient (EFG) to highly asymmetric As surroundings has been revealed. Arsenic atoms form pyramidal structural units in Ge₂As₂Se₇ with no evidence of significant concentration of homopolar bonds. In Ge₂As₂Se₅ most of arsenic atoms form structural units with two As-As bonds per atom and asymmetric EFG distribution. Arsenic bondings become more complicated in Ge_0.33As_0.12Se_0.55 where all arsenic sites are highly distorted. The combination of NQR and NMR data provide valuable information on arsenic bonding dynamics in these glasses.