Knowledge Bank

The combination of a free radical jet source and a Fourier transform spectrometer promises to be a very powerful tool in unravelling complex emission spectra. We have observed the rotationally cool (30 K) spectrum of the 0-0 vibrational band of the $A2\Delta -X2\Pi$ electronic transition of CCl. The spectrum was recorded in emission at high resolution (accuracy of $0.004cm-1$ far the strongest lines) using the Fourier transform spectrometer associated with the McMath Solar Telescope. The CCl radical was produced in a corona excited supersonic expansion in a mixture of $CCl4$ seeded in helium. The first rotational lines of the six strongest branches $(P1,Q1,R1,P2,Q2$ and $R2$) were observed. Transitions in three other branches were also detected $(R12,Q21$ and $R21$), and A-doubling was detected in the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi 1/2$ component of the ground state. the $C37Cl$ isotope structure was only resolved for the $R2$ branch. The spectra obtained and the results of the analysis will be discussed.