Theoretical investigation of zero field splitting parameters for Mn2+ centres in l-asparagine monohydrate

► Zero-field splitting parameters for Mn2+: l- monohydrate are calculated. ► The point-charge model and superposition model are used. ► The calculated parameters agree well with the experimental values. ► The result indicates interstitial occupancy of the impurity ion. ► This is consistent with the notion of earlier workers.