Knowledge Bank

The $(3A2)$ and $B(1A1)$ states of jet-cooled thiophosgene $(Cl2CS)$ have been studied by optical-optical double resonance (OODR) spectroscopy. Two OODR schemes have been used to probe the $B(1A1)$ state. One scheme uses selected vibronic levels of the $A(1A2)$ state as the intermediate state, while the other uses the vibrationless level of the $5(3A2)$ state. All of the vibronic levels in the $33980-35600cm-1$ region can be rationalized with the following *** hand and fundamentals: $00=34277cm-1,\nu 1=505cm-1,\nu 2=470cm-1,\nu 3=213cm-1,\nu 6=249cm-1,42=341cm-1,44=627cm-1.$ The discrepancies among the various studies of the $B(1A1)$ state will be discussed and reconciled. The $a―(3A2)$ state has been studied by a novel OODR scheme which uses the fluorescent vibrationless level of the $B(1A1)$ state to monitor $a―(3A2)-X(1A1)$ transitions. A vibronic analysis has been carried out and the following origin band and fundamentals derived for the $a―(3A2)$ state: $00=17499cm-1,\nu 1=923cm-1,\nu 2=474cm-1,\nu 3=247cm-1,42=297cm-1,44=560cm-1,46=741cm-1$. The results will be compared with those from previous studies. The molecular structures in the $a―(3A2)$ and $B(1A1)$ states will be discussed. It is suggested that the wavenumber of $\nu 6$ in the $A(1A2)$ state is $279cm-1$ instead of $189cm-1$.