Knowledge Bank

Molecular constants of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}$O$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$, $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}$O$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}$O$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}$O$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ for the Fermi diad ($1000,0200$) were obtained using the absolute frequencies measured from laser heterodyne $techniques.1$ The constants were evaluated by a numerical iterative procedure in which the rotational dependent part of the Fermi coupling element, $\delta$J(J + I), was included. The theoretical relations for isotopic substitution for this molecule are well satisfied.