Fourier Transform Emission Spectroscopy of the Aluminum Carbide Molecule

Abstract

The aluminum carbide molecule has been observed for the first time in the gas phase. This simple diatomic molecule was previously known only from matrix isolation ESR studies by Knight et al. [1] and the theoretical calculations of Bauschlicher et al. [2], A fairly strong B4Σ--X4Σ- electronic transition was predicted in the blue [2] analogous to the recendy observed BC molecule [3]. A search was made for this system of AlC in emission from a hollow cathode source using the 1m Fourier transform spectrometer at Kitt Peak National Observatory. The initial search was partially successful in that two weak bands were observed that had the correct form and could not be attributed to any known impurity spectrum. The experiment was repeated using more sensitive detectors and a narrower detection bandwidth, resulting in the spectra described here.