Study on Cu+ off- center dipoles in potassium halides / Estudos sobre dipolos fora de centro de Ions de CU+ em halogenetos alcalinos.

AUTOR(ES)
DATA DE PUBLICAÇÃO

1973

RESUMO

Theoretical and experimental investigations have concluded that Cu+ occupies an off-canter position in several alkali halides. In this work we report results obtained by ionic thermal-currents technique (ITC) to verify the electric dipole properties due to Cu+ ions in off-center position in KC1 crystals. This was developed to study the Cu+ ion behaviour in KBr and KI crystals. The ITC band observed in these crystals geve maxima at 62, 70 and 83 °K, and the activation energies were 0.177, 0.196 end 0.232 eV in KCI, KBr and KI, respectively. From the integration of the ITC bands and the concentration of Cu+ obtained by optical absorption, the dipole moment is determined, giving values of 1.5, 1.9 and 2.6 e Å in KC1, KBr and KI, respectively. Due to the shape of the ITC band, we conclude that the dipole reorientation follows the classical model with a single relaxation time, and that the Cu+ freeze in off-center position below those temperatures where maximum occur at the ITC band.

ASSUNTO(S)

dipolos fora de centro potassium halides cu + halogenetos de potássio cu+ off-center dipoles

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