ROTATIONAL SPECTROSCOPY OF ZnCCH (X$^{2}\Sigma^+$)AT MICROWAVE AND MILLIMETER WAVELENGTHES

Abstract

The pure rotational spectrum of ZnCCH (X$^{2}\Sigma^+$) has been measured using Fourier transform microwave (FTMW) and direct absorption millimeter/submillimeter methods in the frequency range of 7-260 GHz. This is the first study of ZnCCH by any spectroscopic technique. In the FTMW system, the molecule was synthesized using discharge assisted laser ablation spectroscopy (DALAS) from a mixture of 0.05\% acetylene in argon and the ablation of a zinc rod. In the millimeter-wave spectrometer, the radical was created from the reaction of zinc vapor, produced in a Broida-type oven, with HCCH in a DC discharge. Spectra of the main isoplogue, $^{64}$ZnCCH, as well as $^{66}$ZnCCH, $^{68}$ZnCCH, ZnCCD and Zn$^{13}$C$^{13}$CH have been recorded. The data have been analyzed with a $^{2}$$\Sigma$ Hamiltonian and rotational, spin-rotation and H, D and $^{13}$C hyperfine parameters have been determined. The structure is being calculated based on the rotational constants and will be presented. Interpretation of the hyperfine constants will also be discussed.