Knowledge Bank

Parity selected excitation spectra have been recorded of the B-X transition of ArCl2 with 0.05 cm-1 resolution. The resolution is such that rotational structure is clearly evident, but not cleanly resolved. Since simulated spectra using a rigid-rotor model are able to fit the whole spectrum and the even and odd parity selected spectra, we are confident that the spectrum is correctly assigned. $ArCl2$ is found to be a ``T'' shaped molecule with a 3.7 {\AA} distance between the center of the Ar atom and the center of mass of the $Cl2$ molecule. This compares to ArC1F which is a linear molecule with only a 3.3 *** Ar-Cl separation. By measuring the vibrational predissociation threshold, the $Ar-Cl2$ bond energy was found to be $178\pm 1cm-1$ in the B state and $188\pm 1cm-1$ in the X state.