Knowledge Bank

A CS molecular resonance lamp was used to optically pump the $v=0$ vibrational level of the CS $A\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}II$ state. Dipole moments and lambda doublings have been obtained for rotational levels $J=3$ through 9 by Stark Effect-radio frequency resonance experiments. Resonance is detected by monitoring undispersed fluorescence to the $X\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +$ state. In conjunction with optical data$\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$ the measured lambda doublings were used to refine interaction matrix elements for the perturbation of $A1II(v=0)$ by $a1\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma +$. These matrix elements in turn enable one to separate the very small $a\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}\Sigma +$ contribution from the measured dipole moments. A least squares fit to the individual moments measured with 0.3% precision yields $\mu 11=0.65(3),\mu \Sigma =1.7(12)$ Debye.