Knowledge Bank

The jet-cooled high resolution CRDS spectra of the methyl peroxy radical, $CH3OO$ and $CD3OO$ has been obtained for the weak $A~2A\prime \leftarrow X~2A″$ $000$ band. The rotational spectra of the isotopologue species exhibit very different structure. The hindered internal rotational involving methyl and $O2$ groups is a source of this very different structure, due to the strong dependence of the tunneling splitting upon mass through the $F$ parameter ($\sim 4.4cm-1$ for $CD3OO$ compared to $\sim 7.0cm-1$ for $CH3OO$). We will discuss the formalism in the limit of the high torsional barrier in the light of the experimental results, emphasizing the spectral resemblances and differences.