THE VISIBLE SPECTRUM OF THE VINYL RADICAL MEASURED WIHT CAVITY RING-DOWN LASER ABSORPTION SPECTROSCOPY

Abstract

The vinyl radical $(C_{2}H_{3}) \tilde{A}^{2}A^{\prime \prime} \leftarrow \tilde{X}^{2}A^{\prime}$ absorption spectrum has been measured in a room temperature gas cell over the wavelength range 415-530 nm at 0.008 nm resolution using the technique of cavity ring-down laser absorption spectroscopy. The present measurement is 200 times higher resolution than the previously recorded absorption spectrum in this wavelength range. There is considerable lifetime broadening of the observed rotational structure, corresponding to an excited state lifetime of 50 ps. An assignment of the observed vibrational structure will be presented as will preliminary results from jet-cooled spectra.