A MUON INVESTIGATION OF HYDROGEN CENTERS IN CHALCOGENIDE GLASSES

Possible bonding sites of hydrogen in the networks of amorphous Se, Se 1-xAsx, Se1-xSix and Se1-xGex glasses, with x less than or equal to 0. 33, have been investigated by the muon repolarization technique. For a -Se, whose structure is mainly dominated by chains, analysis of the re sults indicates the formation of a centre with highly anisotropic para meters, typical of a molecular radical. In the Se1-xSix and Se1-xGex g lasses, which have two and three dimensional structures with possible atomic cages, a second type of centre with an isotropic electron-muon hyperfine coupling, which scales with the concentration of As, Si or t he Ge, is also formed. The large isotropic electron-muon coupling for this centre implies a trapped-atom state. Possible bonding arrangement s are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.