Knowledge Bank

We have investigated the first and second order Zeeman effect of $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}NH3$ with a beammaser Zeeman spectrometer. Components of the molecular quadrupole tensor have been evaluated from the values for the components of the molecular magnetic moment tensor and the anisotropy tensor of the molecular magnetic susceptibility. The measured Zeeman spectra of the (2,2) inversion level of $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}NH3$ at 20 722.633 MHz and of the (3,3) inversion level at 23 870.128 MHz are interpreted, using the Hamiltonian given by Verhoeven and $Dymanus1$. The primary molecular quantities---the hyperfine coupling constants---are obtained from the least square fit of the observed Zeeman splitting to the theoretical expressions. From the magnetic coupling constants the components of the different molecular magnetic coupling tensors are evaluated. $\to$ The results for the molecular magnetic moment tensor G are {G}{aa}=0.4312(16)\times 10^{-3}\mbox{kHz/G}{G}{ee}-{G}{aa}=-0.0480(24)\times 10^{-3}\mbox{kHz/G} and for the anisotropy tensor {X}{aa}-{X}{ee}=-0.248(15)\times 10^{-6}\mbox{kHz}/{G}^{2} The latter value differs significantly from $Kukolich\prime s2$ result: $Xaa-Xee=-(0.37\pm 0.04)10-6$erg/G$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ The results for the components of the molecular quadrupole tensor $\theta$ are: \theta{cc}=-2.92(8)\times 10^{-26}\mbox{ esu cm}^{2} Details of the experiment will be given and a comparison with ab-initio calculations.