Knowledge Bank

Radiofrequency transitions between the hfs levels of the $J=1$ rotational state in $Rb86F19$ have been observed for molecules in the vibrational states $v=0,1,2,3,4$ using a molecular beam electric resonance spectrometer whose intrinsic line width is less than 1 kc/sec. From these spectra, the variation of the constant $eq1Q1$, which characterizes the interaction between the electric quadrupole moment of the rubidium nucleus and the electric field gradient due to the remainder of the molecule, has been determined as a function of vibrational quantum number, v, for the first five vibrational states. The difference between successive values of $eq1Q1$ exhibit a non-linear dependence on v which is on the order of 1% of the observed linear change with v. The magnitude of the non-linear change is in semi-quantitative agreement with similar measurements made on $LiCl1$ and $LiBr2$. Combination of the present results with the determination of $eq1Q1$ for $v=0$ by Bonezyk and $Hughes3$ gives values of $eq1Q1$ for the first five vibrational states of $Rb85F19$. These are tabulated below where the value of $eq1Q1$ for $v=0$ is that given in reference 3. ""[FIGURE]"" $$\begin{array}{cl}v&\multicolumn{1}{c}{eq_1Q_1/h}\0&-(70,34055 \pm 0.0004),,{\rm mc/sec}\1&-(69,5550 \pm 0.0024)\2&-(68,7784 \pm 0.0042)\3&-(68,0129 \pm 0.0060)\4&-(67,2580 \pm 0.0084)\ \end{array}$$