Nitrogen and chlorine NQR in paraelectric and ferroelectric tris-sarcosine calcium chloride

Abstract

The pure nuclear quadrupole resonance spectra of 14N have been measured in tris-sarcosine calcium chloride (TSCC), deuterated TSCC, and sarcosine using nuclear double resonance in the laboratory frame. In TSCC two chemically nonequivalent nitrogen sites have been found at room temperature, one with a quadrupole coupling constant e2Qq/h =1040 kHz and an asymmetry parameter η=1 and another one with e2Qq/h = 940 kHz, η=1. The 14N results in deuterated TSCC differ from those in undeuterated TSCC by less than 10%. The corresponding 14N data for sarcosine are e2Qq/h = 1440 kHz, η=1 and e2Qq/h = 1470 kHz, η=0.79. In the ferroelectric phase at 77 °K only one nitrogen site has been found in TSCC with e2Qq/h = 1010 kHz and η=0.89. In TSCC, ν (35Cl) =2160 kHz and ν (37Cl) =1710 kHz, and deuterated TSCC 35Cl and 37Cl quadrupole resonance lines were found in the paraelectric phase, whereas in the ferroelectric phase no chlorine lines could be observed.