Knowledge Bank

Pure rotational spectra of the vibrational ground states of H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$AgCl and H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$CuCl have been measured by chirped-pulse FTMW spectroscopy. Each complex is generated via laser ablation of the metal in the presence of small percentages of CCl$\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}$ and C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ in argon. The complexes are stabilized and interrogated in the cold environment of a supersonic jet. Rotational constants ({\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, $\Delta$, have been measured for six isotopologues of H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$AgCl and three isotopologues of H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$CuCl with substitutions at the metal, chlorine and carbon atoms in each case. The spectrum of each complex is consistent with a {\it{C}} structure in which the metal atom is coordinated by the $\pi$-orbital of ethyne. The measured rotational constants allow determination of the length of the bond between the metal and chlorine atoms, {\it{r}}(M{\textemdash}Cl), and the distance between the metal atom and the centre of the ethyne double bond, {\it{r}}(M{\textemdash}*). Nuclear quadrupole coupling constants have been measured for the chlorine atom in each complex and also for copper in H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$C$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$$\cdots$CuCl.