Knowledge Bank

The Stark effect is utilized to ``tune” methyl fluoride energy level spacings into coincidence with the 9.6 $\mu mCO2$ laser lines. Specifically, the $\nu 3$, carbon-fluorine stretch, parallel band is investigated for both $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CH3F$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CH3F$ yielding accurate differences between the molecular constants for the ground state and those of the first excited vibrational state. Dipole moment variation with vibrational quantum number is also studied. The sensitivity of the apparatus is sufficiently high that we can easily observe the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\nu 3-\nu 3$ band for $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CH3F$. Radio-frequency-infrared two-photon spectroscopy is underway to improve the precision of these results.