High pressure transition in amorphous As2S3 studied by EXAFS

We report an in situ high pressure investigation of the structural change in vitreous As2S3 up to 60 GPa using the diamond anvil cell and energy dispersive x-ray absorption spectroscopy. The main finding of the present study is a gradual elongation of the average As-S bond length, which takes place in the pressure range of 15-50 GPa. This change is interpreted as a signature of the coordination number increase around As atoms. The negative shift of the As K absorption edge position confirms the progressive metallization of the glass at high pressure. The observed changes are reversible after pressure release.