Chlorine-35 quadrupole resonance in impurity doped chlorates

The chlorine-35 quadrupole resonance was studied in NaClO₃, KClO₃ and Ba(ClO₃)₂ doped with the bromates and chlorates of various metal ions. Measurements were carried out at 78°K and at room temperature and with impurity concentrations c up to 1·3 mol%. The frequency and the linewidth of the chlorine resonance change linearly with c, but by different amounts at the two temperatures. The frequency shifts caused by the various impurities in the same matrix are proportional to the difference of the electronegativities of the impurity and the substituted host ion. In most of the samples studied no evidence was found for a contribution from elastic distortions. The observed shifts of the quadrupole resonance frequency are attributed to a charge-transfer from the impurity ion to the chlorate molecules.