The lifetimes of positrons in oxides of arsenic and antimony

Abstract

The lifetimes of positrons in crystalline powders of dimeric oxides of arsenic and antimony, and in trioxymethylene and polyoxymethylene are reported. In As₄O₆ and polyoxymethylene a longer component τ₄ is observed in addition to the usually observedt 2 component. The variation of τ₄ with temperature and pressure is studied in As₄O₆. On the basis of these results and the X-ray diffraction pictures, it is suggested that ortho-positronium atoms quenched in intercrystallite regions in As₄O₆ gives rise to τ₄.