Knowledge Bank

The $\upsilon 5$ band manifold of $C3O2$ (due to the CCO bending $\upsilon 5$ vibration at $580.2cm-1$ combined with quanta of the CCC bending vibration $\upsilon 7$) observed by $Halonenetal.1$ has been analyzed using a modified version of the semirigid bendor model previously described by $Bunker2$. The $\upsilon 5$ bending mode is degenerate in the linear molecule limit and the semirigid bender Hamiltonian has been modified to account for the $\upsilon 5$ vibrational angular momentum around the molecules axis in the linear limit, and $\ell$-doubling effects. Several parameters have been obtained, primarily the CC bond length, the effective CCC bending potential in the $\upsilon 5$ state, and the $\varphi 5577$ force constant.