Knowledge Bank

The high fluence 193 nm photodissociaton of toluene has been investigated in a free jet expansion. Laser induced fluorescence spectra of the products show a large number of resolved ro-vibronic bands in the range of 21,000 to $24,500cm-1$. Many of these have been assigned to $C2$ and $C3$. The $C2$ is produced in metastable electronically excited states, and a new band system originating from the $C3\Sigma u\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}$ state has been observed. Two bands of this system, with origins at 22,347.0 and $22,462.5cm-1$, show the simple P and R branch structure of a $\Sigma -\Sigma$ transition. A preliminary rotational analysis yields an upper state rotational constant (for the band at $22,347cm-1$) of $1.91cm-1$, which is significantly larger than the constants for any of the previously characterized excited states. The details of these experiments, and the results from a more extensive analysis of the spectra, will be presented.