Die Temperaturabhängigkeit der Kernquadrupolkopplungskonstante von Na23 in Natriumnitrit, NaNO2

Abstract

The nuclear quadrupole coupling constant of Na23 in sodium nitrite. NaNO2. has been investigated between 18 °C and 215 °C. Below the transition temperature (163 ± 2)°C the asymmetry parameter η= (φxx — φyy)/φzz decreases with increasing temperature and goes to zero at the transition point. Above 163 °C η is negative and | η | increases with temperature. This temperature dependence of the nuclear quadrupole coupling cannot be explained adequately by the point charge model together with the assumption of the free rotation of the NO2-group above the transition point.