Knowledge Bank

The large discrepancy between the value 0.4D {\AA} measured by Buckingham for the quadrupole moment of oxygen and the recent value 1.21D {\AA} used by Yamamoto and Cattani, and by Bouanich, in line broadening calculations is examined. When hexadecapolar and repulsive interactions are included, the discrepancy in the values of the quadrupole moment obtained by the bi-refringence method and line width calculations is at once resolved provided a value of $\Phi \sim$ 6D {\AA}$\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}$ is used for the hexadecapole moment of oxygen.