Knowledge Bank

The radio frequency Stark-Zeeman spectra of the hydrogen fluoride and the hydrogen chloride ($H35Cl$) molecule have been obtained using the molecular-beam electric-resonance method. The measurements are performed in the lowest vibrational state and in the J = 1 rotational state. Computer analysis of the observed spectra gave the following constants: [FIGURE] Using the above values for $gJ$ and $\chi$, $\mathrm{<mrow\; data-mjx-texclass="ORD">-</mrow>}\chi$, we calculated the molecular quadrupole moment for the ground vibrational state of HF and $H35Cl$ as $\theta HF=(2.34\pm 0.03)\times 10-26$ esu $cm2$ and $\theta H35Cl=(3.84\pm 0.08)\times 10-26$ esu $cm2$. The last value has still to be corrected for the vibrational dependence of the paramagnetic part of the rotational magnetic moment. When this dependence has the same sign as in HF, the molecular quadrupole moment of H Cl will drop with approximately $0.10\times 10-26$ esu $cm2$. The components of the diamagnetic shielding tensors are also calculated. The results will be discussed.