Electronic Spectra of C6H+ and C6H3+ in the Gas Phase

Measurement of the Π3−Π3 transition of C6H+ in the gas phase near 19486 cm−1 is reported. The experiment was carried out with a supersonic slit-jet expansion discharge using cavity ringdown absorption spectroscopy. Partly resolved P lines and observation of band heads permitted a rotational contour fit. Spectroscopic constants in the ground and excited-state were determined. The density of ions being sampled is merely 2 × 108 cm−3. Broadening of the spectral lines indicates the excited-state lifetime to be ≈100 ps. The electronic transition of HC6H2+ at 26402 cm−1 assumed to be A11−X 1A1 in C2v symmetry could not be rotationally resolved.

Graphical AbstractFirst detection by cavity ringdown spectroscopy of linear C6H+ in the gas phase within a supersonic expansion followed by a pulsed DC discharge.Figure optionsDownload high-quality image (191 K)Download as PowerPoint slide