Knowledge Bank

A Balle-Flygare FT-MW spectrometer coupled to a laser ablation source has been used to measure the pure rotational spectra of H$\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$AgCl and H$\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$CuCl. Both molecules are generated via laser ablation (532 nm) of a metal rod in the presence of CCl$\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}$, C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$H$\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}$ and argon and are stabilized by supersonic expansion. Rotational constants ({\it{A}}$\mathrm{<mrow\; data-mjx-texclass="ORD">0</mrow>}$, {\it{B}}$\mathrm{<mrow\; data-mjx-texclass="ORD">0</mrow>}$, {\it{C}}$\mathrm{<mrow\; data-mjx-texclass="ORD">0</mrow>}$) and the centrifugal distortion constant, {\it{D}}, have been measured for six isotopologues of H$\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$AgCl and five isotopologues of H$\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$CuCl with substitutions at the metal, chlorine and carbon atoms in each case. The spectrum of each molecule is consistent with a {\it{C}} structure in which the metal atom interacts with the $\pi$-orbital on ethene. The measured rotational constants allow determination of the length of the bond between the metal and chlorine atoms, {\it{r}}, and the distance between the metal atom and the centre of the ethene double bond, {\it{r}}. Nuclear quadrupole coupling constants have been determined for the chlorine atom in each molecule and also for copper in H$\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$CuCl.