Knowledge Bank

The emission of thiophosgene vapor excited by an $Ar+$ laser at 5145 {\AA} consists of resonance fluorescence from the $213141$ vibronic level of the $A~$$\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}A2$ state. Analysis of the partially-resolved rotational structure of the fluorescence shows that the excitation wavelength is absorbed by a cluster of lines belonging to $PP$ branches, and that the radiation selectively excites the $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl2CS$ isotope. About 55 fluorescence bands have been assigned, and the vibrational constants of the ground state have been calculated from the data.