Molecular g-Values, Magnetic Susceptibility Anisotropies, Molecular Quadrupole Moments and the Anisotropies in the Electronic Charge Distribution in HNO 2 -Cis, DNO 2 -Cis, HNO 2 -Trans, and DNO 2 -Trans

The rotational Zeeman effect of the trans and eis forms of nitrous acid has been studied to yield the diagonal elements of the molecular g-tensor and the anisotropics in the diagonal elements of the magnetic susceptibility tensor. The results are used to calculate the diagonal elements of the molecular electric quadrupole moment tensor and the anisotropics in the second moments of the electronic charge distribution for all four molecular species. These data are compared to the corresponding CNDO/2 values, and the CNDO/2 value for the out of plane second moment of the electronic charge distribution is used together with the experimental anisotropics in the second moments of the electronic charge distribution to derive a semiexperimental value for the molecular bulk susceptibility which is otherwise difficult to obtain. The out-of-plane minus average in-plane magnetic susceptibility anisotropy is discussed with reference to the model of localised atomic susceptibilities and it is shown that the model should be extended to include bond and bond-bond interaction contributions.