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= (φ_xx — φ_yy)/φ_zz 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.