Temperature Dependence of theNa23Quadrupole Coupling Constants in Rochelle Salt

The ${\mathrm{Na}}^{23}$ nuclear quadrupole coupling constant in Rochelle salt is found to have a linear dependence on temperature which extends through both the higher- and lower-temperature non-ferroelectric phases. This result necessitates a reinterpretation of some earlier data, but is in perfect agreement with the recent calculations of Žekš, Shulka, and Blinc.