NMR IN KH2PO4 BY DOUBLE RESONANCE METHOD

NMR signals of the potassium in KH2PO4were detected by means of the double resonance technique in the rotating reference frame, and the electric quadrupole coupling constants and associated parameters were determined in the paraelectric (290°K) and ferroelectric (77°K) phases. At 290°K, the electric field gradient at the site of the potassium is axially symmetric (η=0) and |eQq/h|=1.68 MHz for K3939. At 77°K, |eQq/h|=1.479 MHz for K3939 and 1.796 MHz for K4141 with the asymmetry parameter η=0.696. The major principal axis of the electric field gradient tensor coincided with the Z (c)-axis in both phases. The values of the electric field gradient were calculated by using point charge model in both paraelectric and ferroelectric phases and compared with the experimental ones. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.