Characteristics of impurity effects in isomorphous crystals and anisomorphous mixtures observed by 14N nuclear quadrupole resonance

Impurity effects on 14N nuclear quadrupole resonance (NQR) measured at room temperature for various mixed complexes, [NaNO2]–[ANO2] and [(CH2)6N4]–[BNO2] with A=Ag or K and B=Na or K, respectively, have been compared. A classification of these mixed systems into isomorphous mixed crystals and anisomorphous mixtures provides a mean for obtaining systematic trends of impurity effects in these systems. With regard to the 14N NQR at room temperature, the isomorphous system [NaNO2]–[ANO2] is characterized predominantly by the static impurity effect caused by the random static distribution of the impurity ions in the host crystal. The anisomorphous system [(CH2)6N4]–[BNO2] appears to be subject to the dynamic secondary impurity effects due to the mobile point defects inside the matrix of the segregated host crystal.