Knowledge Bank

The microwave spectrum of dichlorosilylene in excited vibrational states has been measured in the millimeter-and submillimeter-wave regions, Rotational and centrifugal distortion constatnts were determined for the $\nu 1,\nu 2,2\nu 2$, and $\nu 3$ excited states of the $Si25Cl2$ isotopic species and for the $\nu 2$ and $2\nu 2$ state of $Si35Cl37Cl$. Analysis of the Coriolis resonance between the $\nu 1$ and $\nu 3$ states of $Si35Cl2$ yielded values of the {D} Coriolis interaction constant with {F} constrained and of two higher-order terms and also an accurate value [$5,402338(95)cm-1$] of the energy difference between the two excited vibrational states. The rotational constants of $Si35Cl2$ in the first excited states of the three normal vibrations were combined with those of the ground vibrational state reported in a previous $paper1$ to obtain the equilibrium structure, harmonic and cubic/third-order anharmonic potential constants.