Electron spin resonance studies of chlorine centres in irradiated chlorine-doped Na2SO4 single crystals
Titel:
Electron spin resonance studies of chlorine centres in irradiated chlorine-doped Na2SO4 single crystals
Auteur:
Suryanarayana, D. Sobhanadri, J.
Verschenen in:
Molecular physics
Paginering:
Jaargang 28 (1974) nr. 5 pagina's 1127-1138
Jaar:
1974-11
Inhoud:
The nature of paramagnetic centres trapped in X-irradiated Na2SO4 single crystals containing chlorine as impurity has been determined from E.S.R. measurements both at room and liquid nitrogen temperatures. ClO3, ClO2, SO4- and O3- are the paramagnetic centres identified. The g and A parameters of ClO3 change considerably between 298 K and 77 K. Thus the parameters of ClO3 obtained at 298 K are gxx = 2·0123, gyy = 2·0143, gzz = 2·0206 G and those of the A-tensor are Axx = 97, Ayy = 100 and Azz = 112 G. The parameters obtained for the same centre at 77 K are gxx = 2·0132, gyy = 2·0173, gzz = 2·0073 G and those of the A-tensor are Axx = 130·6, Ayy = 146·3 and Azz = 181·2 G. The temperature variation of the principal values are determined in the temperature range between 298 K and 77 K. These data can be interpreted on the assumption that ClO3 undergoes libration at room temperature, which is frozen out reversibly on cooling. The structure and mechanism of these defects are discussed further.
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