Knowledge Bank

The spectrum of the AIC molecule has been observed for the first time, in emission from a composite wall hollow cathode source. The 0-0, 1-1, 0-1, 1-2, 2-3 and 3-4 bands of the $B4\Sigma --X4\Sigma +$ system were recorded at Doppler limited resolution with the 1m Fourier transform spectrometer at Kitt Peak National Observatory. The spectrum was fairly weak with a signal-to-noise of about 10 for the strongest lines in the 0-0 band. The bands are blue degraded and show the characteristic constant doubling of a $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -4\Sigma$ transition. The origin is at $22460cm-1$ in excellent agreement with recent high level theoretical calculations [1]. A full analysis of the observed bands will be presented.